Public Land Survey BackgroundNote: This page deals with the U. S. Public Land Survey system at the township and range level. A more detailed discussion, including smaller subdivisions of the system, is available in Adobe PDF format from the U.S. Geological Survey's Rocky Mountain Mapping Center. The freely downloadable Adobe Acrobat Reader is required to view the document. The Public Land Survey (PLS) system was established in 1787 by the Continental Congress for purposes of land division. Beginning in the late 1840s, the federal government began surveying Minnesota as part of the PLS. The survey system typically divides the land into 6-mile-square townships, which are further subdivided into 1-mile-square sections. In most of the U.S., PLS designations are employed for legal land descriptions, transactions and adjudications, and also as location references for geographic data.
Minnesota falls into two township numbering zones. Townships in the
west and south are numbered from the 5th Principal Meridian of the
U.S. PLS system, and those in the northeast from the 4th Principal
Meridian.
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The map at right illustrates the township and range numbering
system in the northwest corner of Minnesota. Township lines
form tiers running east-west across the state, while range
lines form columns running north-south. The squares formed by the
intersection of these tiers and columns are typically referred to
simply as townships, and are identified by the combination of
the township tier number and range column number. In the map, the
highlighted township would be identified as Township 160 North,
Range 48 West, or T160R48 for short.
The two zones, whose main dividing line in Minnesota is
the Mississippi River, are shown in the map at left. In practice, the
distinction is easy to recognize: in Minnesota it happens that all 5th
P.M. township numbers are above 100, and all 4th P.M. township numbers
are below 100. 
A subtler complication arises from the
fact that the 4th Principal Meridian (unlike the 5th) actually passes
through the state, intersecting its northeastern tip as shown at
left. Unlike the 5th P.M. ranges, all of which are numbered westwards
in Minnesota, a small number of 4th P.M. ranges are numbered
eastwards from their meridian. The blue line in the map at
right shows the 4th P.M. and its adjoining ranges in extreme
northeastern Minnesota. Because of this "mirroring" effect on range
numbers, some township/range numberings are duplicated on either side
of the line, and in order to distinguish them, an identifier
indicating direction from the 4th P.M. is appended to the usual
combination of township and range number: T63R2W.
The map at left shows an area slightly larger than four townships,
centered on Pokegama Lake near Grand Rapids, Minnesota. The darker
squares indicate township boundaries, while the lighter squares
indicate section boundaries within townships. These four "standard"
townships each contain a 6 x 6 grid of 1-square-mile sections, making
for a total of 36 square miles per township. Where townships are
bounded by international or state borders or a "seam" in the PLS
system, their shape may be less regular. Note that sections within
townships are numbered beginning in the northeast corner, and that the
numbering system snakes its way back and forth across the township
from north to south, following the tracks of the early surveyors as
they moved across the landscape.
