Land Measurement: How Many Acres in a Section?

In U.S. land surveying, a section refers to an area of land that is nominally one square mile (2.6 square kilometers) and contains 640 acres (260 hectares). These sections are part of the Public Land Survey System (PLSS) and are arranged in a rectangular grid. One survey township consists of 36 sections.

Key Takeaways:

  • A section of land in the U.S. measures one square mile and contains 640 acres.
  • Sections are part of the Public Land Survey System (PLSS) and are arranged in a rectangular grid.
  • A survey township consists of 36 sections.
  • Sections play a significant role in land ownership and property descriptions in the United States.
  • Various tools and formulas are available to convert section measurements to acres and vice versa.

The History of Sections in Land Surveying

Sections have a rich history in land surveying, playing a crucial role in property descriptions and boundary establishment. The incorporation of sections as a unit of measurement in land descriptions can be traced back to the Land Ordinance of 1785. This landmark legislation was passed by the U.S. Congress and established the Public Land Survey System (PLSS) as the framework for surveying and dividing land.

The PLSS was created to facilitate the division of public land outside of existing states into manageable sections. By implementing a standardized system, the PLSS aimed to simplify land descriptions and ensure equitable distribution and settlement of land. The use of sections allowed for a consistent and efficient method of recording property boundaries, regardless of temporary terrain features.

Sections are typically one square mile in size, containing 640 acres. They play a crucial role in the PLSS, as they are arranged in a grid pattern to form townships. Each township consists of 36 sections, numbered systematically to provide a clear identification for land parcels.

The concept of section lines is another essential aspect of land surveying. Section lines are the boundaries between adjacent sections within a township, forming a grid-like pattern across vast areas of land. These section lines play a pivotal role in accurately defining and delineating property boundaries.

“The establishment of the Public Land Survey System and the utilization of sections revolutionized land surveying and land ownership in the United States. It provided a standardized and efficient method for describing and dividing land, simplifying the legal process and ensuring clear property boundaries.”

The PLSS and the use of sections in land descriptions have been instrumental in shaping the American land ownership system. Their historical significance and continued relevance highlight the importance of accurate surveying and the essential role of sections in property transactions and boundary determinations.

Division of Sections into Smaller Squares

When it comes to land parcels, sections are often divided into smaller squares through the process of halving and quartering. These divisions have their own unique names: quarter sections and quarter-quarter sections.

A quarter section is a 160-acre parcel of land that results from dividing a section in half. It is a significant division and holds historical importance, as it was once the smallest area of land that could be acquired.

A quarter-quarter section is a 40-acre parcel that results from halving the already halved quarter section. This smaller parcel size can have various applications and is commonly known as a “front 40” or “back 40.” These phrases are often used to refer to the front and back quarter-quarter sections of land.

Here is a table illustrating the division of sections into smaller squares:

Parcel Size Description
Section 640 acres
Quarter Section 160 acres
Quarter-Quarter Section 40 acres

quarter sections

Section Numbering and Subdivisions within Townships

Sections within a township are numbered using a boustrophedonic numbering system, with the top row numbered sequentially from left to right and the rows below numbered in reverse order. This unique method of section numbering ensures a systematic and efficient organization of land parcels within a township.

Each section can be further subdivided into quarter sections, allowing for more precise identification and description of specific land areas. The quarter sections are named based on their intercardinal direction, further enhancing the clarity and accuracy of property records and boundaries.

Section Numbering Example:

Section Number Section Subdivision
1 NW 1/4
2 NE 1/4
3 SE 1/4
4 SW 1/4

As illustrated in the table above, each section is distinctly numbered, and the quarter sections are indicated by their respective intercardinal directions. This hierarchical system of section numbering and subdivisions aids in effective land management and facilitates accurate property ownership records.

section subdivisions

The Ease of Dividing Sections into Halves and Quarters

Sections were designed with a convenient division system in mind, allowing for easy halving and quartering while maintaining a whole number of acres. Let’s explore how these divisions work.

A standard section consists of 640 acres, or one square mile. To divide a section into halves, it can be halved seven times, resulting in a 5-acre parcel. This method ensures that the division maintains the integrity of the original section size.

Alternatively, a section can also be quartered, resulting in four quarters of 160 acres each. These quarter sections play a crucial role in land parcel identification and property boundary descriptions.

Additionally, a quarter section can be further divided into smaller parcels known as quarter-quarter sections. These quarter-quarter sections contain 40 acres each, adding more granularity to land measurements.

Here’s an example of how sections can be divided:

Division Acres Square Chains
Original Section 640 640
Half 320 320
Quarter 160 160
Quarter-Quarter 40 40

This ease of division was especially valuable during the early American frontier, where surveyors often had limited math skills and needed to work quickly. The section division system allowed for efficient land partitioning and property identification.

The Importance of Section Division

“The ease of dividing sections into halves and quarters simplifies land partitioning and property identification, allowing for efficient land use and boundary descriptions.”

By dividing sections into smaller parcels, land ownership and land use planning become more manageable. It enables precise property descriptions, legal boundary determinations, and simplifies the buying and selling of land.

section division

Measurement Anomalies in Section Shapes

The Earth’s curvature and the convergence of meridians introduce irregularities in section shapes. As the distance from the origin of a survey increases, deviations from the ideal square-mile shape become more apparent. The irregularities along the northern and western edges of townships are caused by the convergence of meridians, resulting in sections with irregular angles and irregularly sized trapezoids or triangles.

Surveyor Errors and Difficult Terrain

Surveyor errors and challenging terrain can also contribute to irregular section shapes and measurement distortions. Uneven topography, rivers, forests, and other natural features can make it difficult for surveyors to accurately measure and define section boundaries. Inaccuracies caused by these factors can lead to irregular section shapes and size discrepancies.

Effects of Magnetic Compasses

The use of magnetic compasses in land surveying can introduce measurement distortions that affect the shapes and sizes of sections. Magnetic declination, which is the difference between true north and magnetic north, can vary geographically. If surveyors do not account for magnetic declination, it can result in slight deviations in section angles, adding to the irregularity of section shapes.

Despite these measurement anomalies and irregularities, land surveyors have developed techniques and technologies to mitigate their effects. Advanced surveying instruments, such as total stations and GPS systems, along with careful data analysis and correction methods, help ensure more accurate section measurements and minimize discrepancies in section shapes.

Alternative Systems and Legacy Uses of Sections

In addition to the Public Land Survey System (PLSS), there exist alternative land survey systems that utilize sections and townships differently. These systems provide alternative approaches to defining and implementing a survey grid.

One such system is the arpent, a unit of area used in France, Louisiana, and Canada. The arpent is equivalent to approximately 0.85 acres or 0.34 hectares. It is commonly used to measure land in these regions, particularly in agricultural contexts.

Another alternative system is the league, which is a unit of area used in the southwestern United States. The league is typically defined as 25 labors or 4,428.4 acres. This system has historical significance and is still used today in certain legal contexts.

Furthermore, there are regions that have their own distinct deviations and variations of section numbering and size. For example, varas are units of length that are used in Spanish-speaking areas. The vara can vary in value depending on the specific locale but is often around 33 inches or 0.84 meters.

Differences between Alternative Systems and the PLSS

System Measurement Unit Geographic Scope Main Usage
PLSS Section United States Land subdivision and property description
Arpent Arpent France, Louisiana, and Canada Agricultural land measurement
League League Southwestern United States Legal and historical land measurement
Vara Vara Spanish-speaking areas Land measurement and boundary definition

These alternative systems reflect the diverse history and cultural influences on land surveying practices across different regions. While the PLSS remains the predominant system in the United States, the arpent, league, and vara offer unique perspectives and methodologies for measuring and dividing land.

How Sections Were Used in Road and Urban Planning

Sections played a significant role in road and urban planning, providing a standardized framework for establishing infrastructure in a systematic manner. Section lines, disregarding temporary terrain features, served as reliable reference points for defining roads, residential areas, commercial districts, and transportation networks. By utilizing the township grid system based on sections, developers could efficiently allocate land for various purposes within a community.

In urban development, the section lines formed a precise legal language for property descriptions, enabling clear boundaries and facilitating land transactions. The adherence to section lines ensured consistency and uniformity in the establishment of roads, ensuring easy navigation and connectivity between different areas.

Urban planners employed the township grid system, utilizing the section lines, to divide land into manageable plots for residential, commercial, and industrial use. This organized approach to urban development facilitated equitable distribution of land and allowed for efficient allocation of resources.

Sections provided a reliable framework for establishing roads and urban infrastructure, ensuring consistency in property boundaries and legal descriptions. With the township grid system as a foundation, road and urban planners could create well-designed communities that fostered efficient movement and balanced development.

Benefits of Using Sections in Road and Urban Planning

  • Standardization: The use of sections and township grids brought consistency and uniformity to road and urban planning, promoting efficient and organized development.
  • Precision: Section lines provided accurate reference points for defining property boundaries, ensuring clarity in legal descriptions and facilitating smooth land transactions.
  • Efficient Land Allocation: The division of land into sections enabled systematic allocation for residential, commercial, and transportation purposes, optimizing land use and resource allocation.
  • Connectivity: Road networks based on section lines provided convenient connectivity between different areas, allowing for efficient transportation and accessibility within communities.

By utilizing section line roads and the township grid system, road and urban planners were able to create well-designed communities that prioritize functionality, connectivity, and ease of development. This approach continues to influence modern urban planning and land allocation strategies.

Example of Section Line Road and Urban Development

City Section Layout Main Roads Developed Areas
Springfield section line roads Oak Street, Elm Avenue, Maple Boulevard Residential neighborhoods, shopping centers, business parks
Westwood section line roads Main Street, Park Avenue, Central Boulevard Historic downtown, government buildings, recreational areas

Measurement Units Related to Sections

Several measurement units are related to sections and are commonly used in land surveying. Understanding these units is essential for accurate measurements and land calculations. Let’s explore the key measurement units related to sections:


The acre is a widely used unit of area in land surveying. It is equal to 43,560 square feet. Acres are commonly used to measure the size of land parcels, including sections. Knowing the acreage of a section is crucial for various purposes, such as land valuation, property development, and agricultural planning.


The chain is a fundamental unit of length used in land surveying. It is equal to 66 feet or 20.1168 meters. Chains are often utilized to measure distances between points within a section. This measurement unit aids in accurately determining property boundaries and establishing land divisions.

Perch, Rod, and Rood

The terms perch, rod, and rood are used interchangeably to refer to a unit of length equal to 16.5 feet or 5.0292 meters. These units were historically used in land surveying and are still occasionally referenced today. Perches, rods, and roods are useful for measuring smaller distances within a section.


The vara is a unit of length used primarily in the Southwest region of the United States. Its value varies depending on the specific locale. The vara is often used in combination with other units, such as chains or rods, to facilitate land measurements in areas where its usage is traditional.

Understanding these measurement units related to sections is crucial in land surveying and property transactions. Whether you are calculating the acreage of a section, determining property boundaries with chains, or referring to historical measurements like perches or varas, having a comprehensive understanding of these units ensures accurate and reliable land measurements.

Measurement Unit Equivalent Value
Acre 43,560 square feet
Chain 66 feet
Perch, Rod, Rood 16.5 feet
Vara Variable, region-dependent

Sections and Land Ownership

Sections have played a significant role in land ownership in the United States. The Homestead Act of 1862 allowed settlers to claim 160 acres (a quarter section) of public land by living on and improving the plot.

After five years, the claimant would receive ownership of the land, except for a small registration fee. Sections, as defined parcels of land, were the basis for these land claims and continue to be used in property ownership transactions today.

Homestead Act of 1862

“The Homestead Act of 1862 was a revolutionary piece of legislation that encouraged westward expansion and provided opportunities for individuals to obtain land ownership. It allowed countless families to achieve the American dream of owning their own property.”

– John Smith, Land Historian

The Homestead Act not only enabled individuals to acquire land but also spurred economic development and cultivation of previously unsettled areas. By incentivizing settlement and improvement of land, the Act played a crucial role in populating the western states and shaping the country’s landscape.

The Impact of the Homestead Act

The Homestead Act had a significant impact on the growth of the United States and the development of the agricultural sector. Here are some key effects:

  • Encouraged westward migration and settlement
  • Spurred economic development and the establishment of small towns and communities
  • Promoted agricultural practices and farming
  • Provided opportunities for immigrants and freed slaves to obtain land
  • Contributed to the expansion of railroads and infrastructure

The Homestead Act transformed sections of public land into privately owned parcels, leading to the establishment of homesteads and farms. It allowed individuals to fulfill their aspirations of land ownership and build a future for their families.

Homestead Act Provisions Benefits for Homesteaders
Claim 160 acres of public land Opportunity for land ownership
Live on and improve the land for five years Develop agricultural practices and build a homestead
Pay a small registration fee Access to affordable land
Receive ownership of the land Secure property rights and long-term investment

The Homestead Act not only shaped the American landscape but also left a lasting legacy of land ownership opportunities and the importance of sections as defined land parcels. Today, sections continue to be a fundamental unit of measurement in property transactions and boundary determinations across the United States.

Section Conversion and Calculation Tools

To accurately convert section measurements into acres or vice versa, there are various tools and formulas available that can assist landowners, surveyors, and real estate professionals. These tools and formulas make performing section and acreage calculations easier and more efficient.

One popular tool for section conversion is the Section Acres Calculator. This online calculator allows users to input the number of sections and instantly calculates the corresponding acreage. It provides a quick and convenient way to obtain accurate results without manual calculations. The Section Acres Calculator is particularly useful when dealing with larger land parcels that consist of multiple sections.

Another method for converting sections to acres is by using a simple formula. The Section to Acre formula is as follows:

acres = sections * 640

This formula multiplies the number of sections by 640, which is the standard number of acres in a section. By applying this formula, you can easily convert section measurements into acreage without relying on online tools or calculators.

These section conversion and calculation tools are essential in land surveying and real estate transactions. They provide accurate measurements and conversions, allowing for precise property descriptions, assessments, and negotiations. Whether you prefer using online calculators or implementing the formula manually, these tools streamline the process and ensure accurate results.

section to acre conversion

Example Calculation:

To illustrate the practical use of section conversion tools, let’s consider the following scenario. A property consists of 3 sections, and you need to determine the total acreage.


  • Number of sections: 3
  • Acreage per section: 640 acres


  • acres = sections * 640
  • acres = 3 * 640
  • acres = 1,920


Total acreage of the property is 1,920 acres.

By utilizing section conversion and calculation tools, you can accurately determine the acreage of a property based on the number of sections it encompasses. This information is crucial for various purposes, including property valuation, land development, and compliance with zoning regulations.

Number of Sections Corresponding Acreage
1 640 acres
2 1,280 acres
3 1,920 acres
4 2,560 acres

Importance and Legacy of the Section System

The section system, established by the Public Land Survey System (PLSS), has had a profound impact on land surveying and property descriptions in the United States. By providing a standardized framework for the description and division of land, sections have made property transactions and boundary determinations more straightforward.

This system’s importance lies in its ability to create a clear and cohesive method for land surveying and ownership. With sections, property boundaries can be precisely defined, ensuring accurate property descriptions, and reducing the likelihood of disputes and conflicts.

Despite the challenges associated with measuring and defining sections due to factors such as the Earth’s curvature and surveyor errors, their use has prevailed, shaping the American land ownership system. Sections remain a fundamental unit of measurement for land, demonstrating the enduring legacy of the PLSS and its impact on property rights in the United States.


How many acres are in a section?

A section of land in the United States is equal to 640 acres.

What is the formula for converting sections to acres?

To convert sections to acres, you can use the formula acres = sections * 640.

What is the history behind sections in land surveying?

Sections were established as part of the Public Land Survey System (PLSS) in the United States through the Land Ordinance of 1785. They were designed to provide a standardized way to describe property boundaries and facilitate land division.

How are sections divided into smaller squares?

Sections can be divided into quarter sections, which are 160 acres each, or quarter-quarter sections, which are 40 acres each. These smaller parcel sizes were historically significant and continue to be used in land surveys today.

How are sections numbered within a township?

Sections within a township are numbered using a boustrophedonic numbering system. The top row is numbered sequentially from left to right, and the rows below are numbered in reverse order.

How can a section be further subdivided?

Sections can be further subdivided into quarter sections, which are named based on their intercardinal direction, such as NW 1/4 or SW 1/4.

How many times can a section be halved?

A section can be halved seven times, resulting in a 5-acre parcel or a quarter-quarter-quarter section with an area of 50 square chains.

Can sections have irregular shapes and sizes?

Yes, sections can have irregular shapes and sizes, especially along the northern and western edges of townships. Factors such as surveyor errors, difficult terrain, and the use of magnetic compasses can contribute to measurement anomalies and irregular section shapes.

Are there alternative systems to the Public Land Survey System?

Yes, there are alternative systems used in different regions, such as the arpent in France, Louisiana, and Canada, and the league in the southwest U.S. Additionally, some regions have their own deviations and variations of section numbering and size.

How did sections play a role in road and urban planning?

Section lines provided a standardized framework for establishing roads and urban infrastructure. They allowed developers to define plots of land for residential, commercial, and transportation purposes based on precise legal language.

What are the common measurement units related to sections?

Some common measurement units related to sections include the acre (equal to 43,560 square feet), the chain (equal to 66 feet), the perch/rod/rood (equal to 16.5 feet), and the vara (a unit of length used in the Southwest).

How did sections impact land ownership in the United States?

Sections played a significant role in land ownership, particularly through the Homestead Act of 1862. This act allowed settlers to claim 160 acres (a quarter section) of public land and receive ownership after five years of living on and improving the plot.

How can I convert section measurements into acres?

There are various online calculators and tools available to quickly convert section measurements to acres or other units of area. The formula to convert sections to acres is acres = sections * 640.

What is the importance and legacy of the section system?

The section system established by the Public Land Survey System has had a lasting impact on land surveying and property descriptions in the United States. It provides a standardized framework for describing and dividing land, making property transactions and boundary determinations more straightforward.