Range Line, PLSS Definition

Range lines are the north-south boundary lines that divide the PLSS grid into columns of townships. Each range line forms the east boundary of one range and the west boundary of the adjacent range to the east. Range lines run true north-south, making them lines of longitude — they converge slightly toward the north as all meridians do on the spherical Earth.

The principal meridian itself is the most prominent range line — it separates ranges numbered east from those numbered west. Guide meridians, established at 24-mile intervals, serve as supplementary range lines that reset the convergence correction at standard parallels. Between the principal meridian and each guide meridian, individual range lines separate the columns of townships.

In rural areas across the Great Plains and Mountain West, range lines are often reflected in the landscape as the north-south roads that follow township grid boundaries. County roads are frequently built along section lines and range lines, creating the characteristic grid pattern of rural roads visible in aerial photography. A driver heading due north on a county road in Kansas or Nebraska is often following a range line or section line surveyed in the 19th century.

The spacing between range lines is nominally six miles, but because they are true meridians, the actual east-west distance between adjacent range lines decreases slightly moving north. At 45° north latitude, six miles of longitude is slightly less than six miles of distance on the ground. This is why the northern tiers of townships in many states are slightly narrower than the southern tiers — a consequence of Earth's geometry that the PLSS correction system manages but cannot entirely eliminate.