The Public Land Survey System was presented to the Continental Congress in May of 1784 by a committee chaired by Thomas Jefferson. The system became law on May 20, 1785, by an Ordinance for ascertaining the mode of disposing of lands in the western territory. This ordinance was later amended in 1786, 1796, 1800, 1805, and 1812.

The PLS covers all U.S. land that was not settled by the time of the “Official Government Survey”. It does not include the east coast states including Kentucky & Tennessee, or Texas. Small areas of other States that were settled before the survey also technically excluded. This explains the odd shapes of many mining claims in the west. Several survey areas were used throughout the U.S., and many “duly appointed Government Surveyors” laid out Sections, Townships and Ranges across our country over many years.

The lands to be delineated using the Public Land Survey were to be surveyed into Townships, ±6 miles square, and further subdivided into Sections each 1 mile square.

Two lines were used as the origin of each area of survey. The two lines of each of the survey areas were named: Principal Meridian (running true north-south), and Baseline (which ran east-west). Each Principal Meridian and Baseline ran to the limits of the intended survey area.

These two lines intersected at what was called the “initial point”. There are several “initial points” across the U.S. Each of the initial points were established by astronomical observations.

Parallel to the Principal Meridian(s) are “Ranges” of Townships that are numbered east-west of the Principal Meridian. These Ranges, are similar to “columns” of Townships. Ranges are numbered and referred to as “east of the Principal Meridian” or “west of the Principal Meridian”.

Running east-west, are rows of Townships, referred to as “Tiers”. These Township (tiers) are numbered north or south of the baseline.

(Ranges could be compared to the columns of a spreadsheet, while Tiers are laid out like rows).

There are 35 Principal Meridians in the PLSS based on 37 initial points. The PLS was, and is still the foundation of describing and surveying real property in most of the United States, including Alaska.

The PLSS was intended to derive square sections of land, one mile square. But because meridians converge as you travel “true north”, it is mathematically impossible to get 36 square Sections in each Township.