Range

In the Public Land Survey System (PLSS), a range is a north-south column of townships, numbered east or west from the principal meridian. "R. 20 E." is the twentieth column east of the meridian.

BLM's Glossary of Surveying and Mapping Terms defines a range as "a north-south tier of townships or sections," and a range of townships is described by its relationship to the principal meridian.

How ranges are laid out

BLM's Specifications for Descriptions of Land (2017) explains that after the principal meridian and base line are set, "range lines" are established east and west of the principal meridian at 6-mile intervals and numbered east or west of it as necessary. With the township lines, they form the nominal 6-mile-square township. BLM's Manual of Surveying Instructions (2009) numbers ranges "to the east or west beginning with number 1 at the principal meridian" (section 3-3).

Range lines

The township boundaries running north and south are "range lines," and those running east and west are "township lines" (Manual section 1-30). The glossary adds that "with few exceptions the range lines are run on cardinal and have been intended to be on cardinal." Meridional township boundaries are "run from south to north on true meridians" (section 3-18).

Convergence and offsets

Range lines point toward the pole. The Manual explains that they are great circles that, if extended, "would converge and intersect at the North Pole," so townships narrow toward the north. The convergency "is taken up at intervals by the running of standard parallels, on which the measurements are again made full" (section 1-30). Guide meridians are run north "at intervals of 24 miles east and west from the principal meridian" (section 3-14). Because measurement restarts on each standard parallel, range lines jog where they meet one.

How ranges are written

The Specifications give the forms:

• R. for one range and Rs. for more than one
• "T. 13 N., R. 11 E." for one township
• "Tps. 3 S., Rs. 16 and 17 W." for two townships in adjacent ranges
• "Tps. 1 thru 4 S., Rs. 6 thru 9 E." for 16 townships

Not every range is whole. The glossary notes that "half ranges and half townships are fractional townships."

The same range numbers repeat under every principal meridian, so a range means nothing until the meridian is named.

Why it matters in research

East and west are easy to reverse when copying records. R. 20 E. and R. 20 W. under the same meridian lie on opposite sides of the principal meridian, dozens of townships apart. A mining claim record, lease, or county document with the wrong range direction describes land in a different part of the state, and mining claim research has to catch it before anything is plotted.