What is the PLSS? Township, Range, and Section Explained

You're looking at a BLM mining claim record and you see something like "T14N R8E S22." What does that mean? Or the claim lists its PLSS_DESC as "N2NWNE" — and you're supposed to figure out exactly where on a 640-acre section that claim sits.

The PLSS was designed in the 1780s to survey and divide the frontier land of the new United States into orderly, saleable parcels. It's been in use for over 240 years and underpins virtually every federal land record in the west. Once you understand the logic, reading a PLSS description becomes second nature.

Where the PLSS Applies — and Where It Doesn't

The PLSS covers 30 states — primarily the west, midwest, and Great Lakes region. It does NOT cover the original 13 colonies, Texas (which retained its own lands after joining the union), Hawaii, or most of the original territories governed by Spanish/French land grants.

For prospectors this matters: if you're working in Virginia, Georgia, Tennessee, or Texas, you won't find PLSS descriptions on state land records because those states use metes-and-bounds surveys instead. BLM claims only exist on federal public domain land, which is primarily in the 11 western states.

The Base Units: Principal Meridians, Baselines, and Townships

The PLSS starts with a principal meridian — a north-south reference line — and a baseline — an east-west reference line. The continental US has 37 principal meridians. In Nevada and California, surveys are referenced from the Mount Diablo Meridian. In Arizona, the Gila and Salt River Meridian. In Wyoming and Colorado, the Sixth Principal Meridian.

From the principal meridian, the land is divided into townships: 6-mile-square blocks arranged in a grid. A township's address is its position relative to the baseline (north or south) and its range relative to the principal meridian (east or west). "Township 14 North, Range 8 East" (T14N R8E) means the block that sits 14 townships north of the baseline and 8 ranges east of the principal meridian.

Sections: The 640-Acre Unit

Each township is divided into 36 sections, each covering one square mile (640 acres). Sections are numbered starting at the northeast corner of the township, running west to east across the first row, then doubling back east to west across the second row, and so on — a boustrophedon pattern (ancient Greek for "as the ox plows").

Section 1 is always in the northeast corner. Section 6 in the northwest. Section 36 in the southeast. "T14N R8E S22" means Section 22 of Township 14 North, Range 8 East — a specific 640-acre block you can find on any PLSS map.

Quarter Sections: Breaking Down the 640 Acres

A section is divided into four quarter sections of 160 acres each, named by their compass direction: NE¼, NW¼, SW¼, SE¼. Each quarter section covers 160 acres — a standard 20-acre association placer claim covers an eighth of a quarter section.

You can subdivide further: the NW¼ of the NE¼ is a quarter-quarter section of 40 acres. The N½ of the NW¼ of the NE¼ is 20 acres. This is the aliquot notation system — and it's exactly how BLM MLRS records describe the precise footprint of a mining claim.

Why PLSS Matters for Mining Claims

Every BLM mining claim in the MLRS system is described using PLSS notation. The legal land description on your Notice of Location must use PLSS to pinpoint your claim. The BLM uses PLSS to map claim boundaries and identify adjacent or overlapping locations.

The PLSS_DESC field in MLRS — which you'll see if you query raw BLM data — contains the aliquot description of the claim's precise footprint within a section. AuthoriProspector parses this field to shade the exact 20-acre aliquot that's claimed, rather than coloring the entire 160-acre section block.