Township and range in TOPO 24K maps

The Bureau of Land Management (BLM) oversees the division and description of Public Domain land in the U.S. In most states, there are two main perpendicular lines: Principal Meridian and Base Line, which are used to define Townships in conjunction with Township and Range lines. Townships typically cover 36 square miles and are further broken down into thirty-six "1 square mile" Sections.

The Principal (or Prime) Meridian runs north and south, while the Base Line runs east and west. Township designations indicate the location north or south of the Base Line and Range designations indicate the location east or west of the Principal Meridian.

In the illustration above the blue box represents the Township and Range coordinates, T2N R2W. The Township is 2 squares north of the Base Line and 2 squares west of the Principal Meridian.