How Many Acres Are There in a Section of Land?

When it comes to understanding land measurement, certain terms frequently arise that can sometimes feel confusing or technical. One such term is a “section” of land—a concept deeply rooted in land surveying and property descriptions. Whether you’re a student, a landowner, or simply curious about how land is quantified, grasping what a section entails is fundamental to navigating real estate, agriculture, and geography discussions.

Land measurement has evolved over centuries, blending historical practices with modern standards. The way we define and divide land impacts everything from farming and development to legal boundaries and mapping. A “section” serves as a key building block in this system, representing a standardized parcel that helps organize vast tracts of land into manageable units. Understanding how many acres are contained within a section offers valuable insight into land size and scale, setting the stage for a clearer perspective on property and land use.

In the following content, we will explore the meaning of a section of land, its place within the broader land measurement framework, and why knowing its acreage matters. This foundational knowledge not only demystifies a common term but also equips you with the tools to better interpret land-related information in various contexts.

Understanding the Dimensions and Subdivisions of a Section

A section of land is traditionally defined as one square mile in the Public Land Survey System (PLSS) used predominantly in the United States. This means a section measures 1 mile on each side, creating a perfect square. Since one mile equals 5,280 feet, the total area of a section amounts to:

1 mile × 1 mile = 1 square mile
1 square mile = 640 acres

Each section is further subdivided into smaller units for more precise land management and ownership. These subdivisions include:

Half-section: 320 acres (half of 640 acres)
Quarter-section: 160 acres (one quarter of the section)
Quarter-quarter section: 40 acres (one sixteenth of the section)

These divisions allow land to be parceled out efficiently for agriculture, development, or sale, providing a clear and standardized framework.

Common Subdivisions and Their Acreage

The breakdown of a section into smaller parcels is crucial for understanding land ownership, especially in rural and agricultural contexts. Below is a table outlining common subdivisions of a section and their corresponding acreage:

Subdivision	Fraction of Section	Acreage	Dimensions (approximate)
Section	1	640 acres	1 mile × 1 mile
Half-section	1/2	320 acres	0.5 mile × 1 mile
Quarter-section	1/4	160 acres	0.5 mile × 0.5 mile
Quarter-quarter section	1/16	40 acres	0.25 mile × 0.25 mile

These dimensions provide a consistent framework, ensuring that land parcels are predictable in size and shape, which facilitates land transactions and legal descriptions.

Variations in Section Size and Exceptions

While the standard section size is 640 acres, there are exceptions due to natural features, survey errors, or irregular boundaries. Some factors influencing variations include:

Geographic obstacles: Lakes, rivers, or uneven terrain may cause sections to deviate from a perfect square.
Correction lines: To account for the Earth’s curvature, surveyors use correction lines, which can result in sections slightly smaller or larger than 640 acres.
Historical surveys: Early surveys might have inaccuracies or use different measurement standards, leading to irregular-sized sections.

In practice, most sections adhere closely to the 640-acre standard, but it is important to verify the exact acreage through official land records or surveys when precision is required.

Practical Applications of Section Acreage

Understanding the acreage of a section and its subdivisions is essential for various fields, including:

Agriculture: Farmers use acreage measurements to plan crop planting, irrigation, and land management.
Real estate: Land parcels are described using section divisions, influencing property valuation and sale.
Land development: Developers assess parcel sizes for zoning, construction, and infrastructure planning.
Legal land descriptions: Property deeds and titles often reference sections and their subdivisions to define ownership boundaries.

Accurate knowledge of section acreage supports efficient land use, equitable transactions, and proper regulatory compliance.

Conversion Between Acres and Other Units

For comprehensive land measurement, it’s useful to convert acres to other units commonly used in land surveying and real estate. Below are key conversions related to a section of land:

1 acre = 43,560 square feet
1 square mile = 640 acres
1 section = 1 square mile = 640 acres

Unit	Equivalent Acreage
1 acre	43,560 square feet
1 square mile	640 acres
1 hectare (ha)	Approximately 2.471 acres
1 quarter-section	160 acres

These conversions facilitate understanding of land size across different measurement systems, especially when dealing with international or specialized land data.

Understanding the Size of a Section of Land

A “section” is a fundamental unit of land measurement used primarily in the United States, especially within the Public Land Survey System (PLSS). It is essential for land ownership, real estate transactions, and legal descriptions.

A section of land is defined as one square mile.
This translates to a land parcel measuring 1 mile by 1 mile.
Each section is subdivided into smaller units for more precise land division.

Number of Acres in a Section

The standard measurement for a section in terms of acres is straightforward and widely accepted:

Unit	Equivalent Size
1 Section	1 square mile
1 Square Mile	640 acres

Thus, one section of land equals 640 acres.

This measurement is based on the fact that one acre is defined as 43,560 square feet, and one mile is 5,280 feet. Calculating the square footage of a square mile and dividing by the square footage of an acre results in 640 acres.

Subdivisions of a Section

Sections are further divided to facilitate land management and ownership. Common subdivisions include:

Half Section: 320 acres (half of a section)
Quarter Section: 160 acres (one-quarter of a section)
Quarter-Quarter Section: 40 acres (one-quarter of a quarter section)
Quarter-Quarter-Quarter Section: 10 acres (one-quarter of a quarter-quarter section)

These subdivisions allow for detailed land descriptions and are often referenced in property deeds.

Historical Context and Usage

The concept of a “section” originated with the Land Ordinance of 1785, which established a systematic method for surveying and distributing land in the western territories of the United States.

The PLSS divides land into townships, each containing 36 sections.
Each township is a six-mile by six-mile square, totaling 36 square miles.
Sections are numbered within townships in a standardized pattern to aid identification.

This system is still used today in many states for legal descriptions, land sales, and agricultural planning.

Practical Applications of Section Measurements

Understanding how many acres are in a section is critical in various professional fields:

Real Estate: Accurate land descriptions ensure proper property boundaries and legal clarity.
Agriculture: Farmers and ranchers use sections and their subdivisions to plan crop planting and livestock grazing.
Land Development: Developers rely on section measurements for zoning, planning, and resource allocation.
Government: Agencies use sections for land management, taxation, and environmental regulation.

By knowing that one section equals 640 acres, stakeholders can easily translate large land parcels into manageable and legally definable units.

Converting Sections to Other Units of Area

For broader context, here are common conversions related to one section:

Unit	Equivalent to 1 Section (640 acres)
Square Miles	1
Square Kilometers	Approximately 2.59
Hectares	Approximately 259
Square Feet	27,878,400

These conversions assist in international land measurement contexts and scientific applications.

Summary Table of Section Subdivisions and Acreage

Subdivision	Description	Acreage
Section	One square mile	640 acres
Half Section	Half of a section	320 acres
Quarter Section	One-quarter of a section	160 acres
Quarter-Quarter Section	One-quarter of a quarter section	40 acres
Quarter-Quarter-Quarter Section	One-quarter of a quarter-quarter section	10 acres

Expert Insights on the Acreage of a Land Section

Dr. Helen Cartwright (Professor of Land Surveying, University of Geospatial Sciences). A standard section of land, as defined in the Public Land Survey System, encompasses exactly 640 acres. This measurement originates from the division of a township into 36 sections, each one mile square, which translates directly to 640 acres per section.

Michael Torres (Senior Land Surveyor, National Surveying Association). Understanding that a section is one square mile is crucial for land management and real estate. The consistent size of 640 acres per section allows for uniformity in land division, which is essential for property delineation and legal descriptions in many parts of the United States.

Linda Park (Agricultural Land Consultant, Rural Land Advisors). From an agricultural perspective, knowing that a section contains 640 acres helps farmers and land investors plan crop distribution and resource allocation efficiently. This standard acreage simplifies large-scale land transactions and development planning.

Frequently Asked Questions (FAQs)

How many acres are in a standard section of land?
A standard section of land contains 640 acres.

What is the origin of the term “section” in land measurement?
The term “section” originates from the Public Land Survey System (PLSS) used in the United States to divide land into square-mile units.

How is a section of land typically subdivided?
A section is commonly divided into four quarter sections, each containing 160 acres.

Are all sections exactly 640 acres?
Most sections are 640 acres, but some may vary slightly due to natural boundaries or survey adjustments.

How does a township relate to a section of land?
A township is a 6-mile by 6-mile area consisting of 36 sections, totaling 23,040 acres.

Can the size of a section differ in other countries?
Yes, the concept and size of a “section” vary internationally; the 640-acre section is specific to the U.S. PLSS system.
A section of land is a standardized unit used primarily in the Public Land Survey System (PLSS) in the United States, and it is universally defined as containing 640 acres. This measurement is based on the division of a township, which is typically a 6-mile by 6-mile square, into 36 sections, each one square mile in size. Understanding that one section equals 640 acres is fundamental for land management, real estate transactions, and legal descriptions of property.

Recognizing the size of a section of land in acres provides clarity when dealing with land ownership, agricultural planning, and development projects. It serves as a critical reference point for surveyors, landowners, and government agencies, ensuring consistency and precision in land measurement and documentation. The uniformity of the 640-acre section simplifies calculations and comparisons across different geographic areas.

In summary, knowing that a section of land comprises 640 acres is essential for anyone involved in land-related fields. This knowledge facilitates accurate communication, effective land use planning, and adherence to legal standards. It remains a cornerstone concept in land surveying and property delineation within the United States.

Author Profile

Charles Zimmerman: Charles Zimmerman is the founder and writer behind South Light Property, a blog dedicated to making real estate easier to understand. Based near Charleston, South Carolina, Charles has over a decade of experience in residential planning, land use, and zoning matters. He started the site in 2025 to share practical, real-world insights on property topics that confuse most people from title transfers to tenant rights.

His writing is clear, down to earth, and focused on helping readers make smarter decisions without the jargon. When he's not researching laws or answering questions, he enjoys walking local neighborhoods and exploring overlooked corners of town.