Township and Range Mapping

The Township and Range coordinate system has been used since the 1790s to survey public lands in the United States. Technically, the official name of this system is the Public Land Rectangular Survey (PLS), but in practical use, most people call it Township and Range.

This coordinate system was developed after the American Revolution as a way to survey and grant title to land that was newly acquired following the country’s independence. Thomas Jefferson helped develop the system, which was enacted under the Northwest Land Ordinance of 1785. Township and Range isn’t used in the eastern United States (or in a few other states) because land surveys in those states had been completed. The system is based on the following components:

• Meridians and baselines. These lines are the foundation of the Township and Range system:
• Meridians are imaginary lines that run north to south.
• Baselines are lines that run east to west.
• An initial point is where a meridian and a baseline meet. The California Bureau of Land Management has a nice online map of all the meridians and baselines at www.ca.blm.gov/pa/cadastral/ meridian.html.
• Townships: Townships are the horizontal part of the coordinate system.
• Each township is six square miles in size.
• Townships are identified by whole numbers starting with 1.
• The first township at the intersection of a meridian and baseline is 1, the next township is 2, and so on.
• If a township is north of the baseline, it’s identified with an N; if it’s south of the baseline, it’s designated with an S. For example, the fifth township north of a meridian and baseline is T. 5 N.
  
• Ranges: Ranges are the vertical part of the grid scale.
• Ranges are six miles wide.
• Ranges are numbered starting at the intersection of the meridian and the baseline.
• In addition to a number, a range is identified as being east or west of a meridian. For example, the third range west of the meridian and baseline is R. 3 W.

The intersection of a township and range (a 36-square mile parcel of land) also is also called a township. This bit of semantics shouldn’t have an effect on you using the coordinate system, but watch out for someone else doing this.
Like other coordinate systems, Township and Range uses smaller measurement
units to identify a precise location. These units include

• Sections: A 36-square-mile township is further divided into 36 one-mile squares called sections. Sections are numbered 1–36. Number 1 starts in the top, right of the township, and the numbers sequentially snake back and forth across the section, ending at number 36 in the bottom-right corner.
  
• Quarters: Sections are divided even further by slicing them into quarters.
• Quarters are identified by the part of the section they occupy, such as northwest, northeast, southwest, or southeast.
• You can further narrow the location with quarter quarters or quarter quarter-quarters.

Township and Range coordinates are a hodgepodge of abbreviations and numbers that lack the mathematical precision of latitude and longitude or UTM. For example, the Township and Range coordinates of Dillon Falls are

SE ¼ of SW ¼ of NE ¼, Sect. 4, T. 19 S, R. 11 E, Willamette Meridian

To describe a location with this coordinate system, you start from the smallest chunk of land and then work your way up to larger chunks. Some people ignore this convention and reverse the order, skip the meridian, or use both halves and quarters. (Hey, it keeps life interesting. . . .) Although scanned paper maps (such as USGS topographic maps) often show township and range information, most digital mapping software and GPS receivers don’t support township and range. This is good news because latitude and longitude and UTM are much easier to use. Township and range information usually is omitted from digital maps because

• The coordinate system is difficult to mathematically model.
• Townships and sections may be oddly shaped because of previously granted lands, surveying errors, and adjustments for the curvature of the earth.

Peter Dana’s comprehensive Geographer’s Craft Web site has lots of good technical information on coordinate systems:
www.colorado.edu/geography/gcraft/notes/coordsys/coordsys.html