Government Survey System: Townships, Sections & Acreages Explained

The government survey system — also called the rectangular survey system or the Public Land Survey System (PLSS) — is a federal method of dividing land in the United States into townships, sections, and acreages using a grid of baselines and principal meridians. Established by the Land Ordinance of 1785, it is used in 30 states and remains one of the most tested topics on the real estate licensing exam.

Survey systems are the government's way of subdividing land for identification, sale, and ownership — making it possible to describe any parcel's exact location using a standardized legal description.

What is a Governmental Survey System?

A government survey system, also known as the rectangular survey system, is a federal land survey system created by the Land Ordinance in 1785. 

Due to the continuous growth in the United States territory, the need arose for a system through which property owners could identify their real property. 

The rectangular survey system was one of the ways developed to achieve this. 

It is a system based on the principle of meridian lines – running from north to south – and baselines – running from east to west – across most of the United States. 

It is used to identify the specific location of land, divide, measure, and create boundary lines to aid the sale of these lands and settle disputes among property owners. 

This system has also been used to prevent survey fraud and simplify land allocation for different purposes, such as schools and urban development. 

How Does the Government Survey System Work?

The government survey system describes real property using the following structure:

• Two reference lines are drawn from the Fixed Point of Beginning -this is a surveyor's mark at a well-known landmark that serves as the starting location from which the baselines and principal meridians are drawn to survey the land 
• The two reference lines drawn are called the Principal Meridian -a line running from north to south- and the Baseline -a line running from east to west 
• From the Fixed Point of Beginning, parallel lines running east to west are drawn from the Baseline, while parallel lines running north to south are drawn from the Principal Meridian. These lines are called tiers (townships) and range lines, measuring approximately 6 miles each. 
• An intersection between two range lines and two township lines forms a township
• To locate a feature on the landscape using a land description, you need to work from the largest to the smallest part.

Having highlighted the lines, their names, and their positions, let’s break things down by taking a quick example, using the coordinates “NW1/4 of NE1/4 of Section 8, T.2N., R.1E”. 

These coordinates translate to the “Northwest quarter of the Northeast quarter of Section 8 in Township 2 North and Range 1 East.” 

How to Read a Legal Land Description

Reading a legal land description in the rectangular survey system can be tricky at first, but the key is to work backward — from the smallest unit to the largest. Here is a step-by-step approach:

1. Start with the section number. This tells you which of the 36 sections within the township your parcel is in.
2. Identify the township and range. Township tells you how far north or south the parcel is from the baseline. Range tells you how far east or west it is from the principal meridian. For example, T3N, R2W means Township 3 North, Range 2 West.
3. Read the quarter descriptions from right to left. The description "NW¼ of NE¼ of Section 12" means: start with Section 12, take the northeast quarter, then take the northwest quarter of that. This narrows your parcel down to 40 acres.

A quick formula to remember for the real estate exam: divide 640 acres by 2 for each "half" and by 4 for each "quarter" in the description. So the "SW¼ of the NW¼ of a section" equals 640 ÷ 4 ÷ 4 = 40 acres.

What is a Township?

A township is established by the intersection of tiers and range lines that measure 6 miles by 6 miles on each side. It comprises 36 sections, with a total area of 36 square miles. 

These sections are numbered beginning from the North East, with the first section designated as 1, all through to 36.

For a clearer understanding, draw a large square and divide it into 36 smaller units. Start numbering each box, beginning from the top right corner to the top left corner, then downward in a snake formation until you have gotten to the last box at the lowest right corner.

Many people take townships to be the same as cities, but this is incorrect. While a township is merely a subdivision of a county or a town, a city is a much larger territory that is even bigger than a town.  

How Many Sections Are in a Township?

A township contains exactly 36 sections. Each section is one square mile (640 acres), and the 36 sections together make up the full 6-mile-by-6-mile township grid. This is one of the most commonly tested facts on the real estate licensing exam.

What is a Section?

A section is one of the basic units in a government survey system. It is a measure of land in a township with a one-mile square of 640 acres. 

The land is referred to as half and quarter sections in each section. The one-sixteenth division of a section is called a quarter of a quarter, as in the NW1/4 of the NW1/4. 

Quick-Reference: Township, Section & Acreage Conversions

Here are the key measurements you need to know:

• 1 Township = 6 miles × 6 miles = 36 square miles = 36 sections
• 1 Section = 1 square mile = 640 acres
• ½ Section = 320 acres
• ¼ Section = 160 acres
• ¼ of a ¼ Section = 40 acres

These conversions come up frequently on real estate exams. A helpful trick: start with 640 and divide by 4 for each "quarter" and by 2 for each "half" in a legal description.

What is an Acreage

An acre is a unit of area used to describe a precise amount of land. It typically measures approximately 43,560 square feet, which translates to 4,046.86 square meters, 0.404686 hectares, or 1/640 of a square mile. An average single-family house sits on only about ⅕ of a total acre. 

Therefore, to clearly understand how big an acre is, picture the American football field but without the end zones. If you use an NBA basketball court, which measures approximately 0.11, one acre will equal approximately 9 basketball courts.

It is important not to confuse an acre with a commercial acre, as these terms describe different things. A commercial acre is a term typically used when describing industrial or commercial properties in big cities. 

It measures about 4,000 square yards instead of 4,840 square yards for a typical acre. This means a commercial acre is roughly 83% of a standard acre.

What is 640 Acres Called?

In the government survey system, 640 acres is called a section. A section is the fundamental building block of the PLSS and represents one square mile of land. Each township is made up of 36 sections, for a total of 23,040 acres per township. This is a frequently asked question on the real estate licensing exam.

What is a Hectare?

A hectare is a unit of area that measures about 10,000 square meters or approximately 2.471 acres. Hence, it is roughly two times larger than an acre. 

To visualize how big a hectare is, picture an international rugby union field measuring approximately 1.008 hectares or a baseball field measuring roughly 0.83 to 1.12 hectares.

If you are not a die-hard sports fan, try picturing London's Trafalgar Square, which is approximately 1 hectare.

Which States Use the Rectangular Survey System?

The rectangular survey system (PLSS) is used in 30 of the 50 U.S. states. It applies primarily to states west of the Ohio River and states admitted to the Union after the original 13 colonies. States that use the PLSS include Alabama, Alaska, Arizona, Arkansas, California, Colorado, Florida, Idaho, Illinois, Indiana, Iowa, Kansas, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico, North Dakota, Ohio, Oklahoma, Oregon, South Dakota, Utah, Washington, Wisconsin, and Wyoming.

States in the eastern U.S. — including the original 13 colonies plus Hawaii, Kentucky, Maine, Tennessee, Texas, Vermont, and West Virginia — generally use the metes and bounds system instead.

Government Survey System vs. Metes and Bounds

The two most common methods of land description in the United States are the rectangular survey system and the metes and bounds system. Understanding the difference is important for the real estate exam.

The rectangular survey system (PLSS) uses a grid of baselines, principal meridians, townships, and sections to identify land. It is systematic, standardized, and used primarily in the western and central United States.

The metes and bounds system uses physical landmarks, directions, and distances to describe the boundaries of a parcel. Descriptions often start at a "point of beginning" and trace the boundary using compass directions and measured distances. This system is the older of the two and is used primarily in the original 13 colonies and a handful of other eastern states.

The key difference is that the rectangular survey system creates a uniform grid, while metes and bounds descriptions are unique to each parcel and rely on natural or man-made landmarks that can change over time.

Final Thoughts on Survey Systems

The government survey system is one of the systems of land description used in most states in the U.S. 

It is a system based on the principles of lines drawn to divide the land into smaller sections for easy identification, purchase, and allocation. It also helps to prevent and settle boundary disputes among property owners.

Practice Questions for the Real Estate Exam

Test your understanding of the government survey system with these practice questions:

1. How many acres are in a section?A section contains 640 acres (1 square mile).

2. How many sections make up one township?A township contains 36 sections, arranged in a 6×6 grid.

3. A legal description reads "the NE¼ of the SW¼ of Section 10." How many acres does this parcel contain?640 ÷ 4 ÷ 4 = 40 acres.

4. What is the difference between a baseline and a principal meridian?A baseline runs east to west; a principal meridian runs north to south. Both originate from the same fixed point of beginning.

5. Which land description system uses a grid of townships, ranges, and sections?The rectangular survey system (also called the government survey system or PLSS).