The rectangular (government) survey system
The rectangular survey system, officially the Public Land Survey System (PLSS) and often called the government survey, divides land into a grid of squares. It is run by the federal Bureau of Land Management (BLM). Instead of walking a boundary, you describe land by where it sits in the grid.
Meridians and base lines
Each survey area starts at an initial point. Through it the surveyors ran two lines:
- A principal meridian, running north and south.
- A base line, running east and west.
Every township in that survey area is located by counting from those two lines.
Florida: the Tallahassee Meridian
All of Florida's PLSS townships are referenced to one principal meridian, the Tallahassee Meridian (that is how BLM's national survey records label every Florida township). The initial point is in Tallahassee. Florida law preserves it in a small park: Fla. Stat. 258.08 sets aside a half-acre square centered on "the intersection of the guide meridian and the base parallel of Florida," the point from which the state was surveyed. Florida has townships both north and south of the base line, and ranges both east and west of the meridian.
Townships, ranges and tiers
From the meridian and base line, the land is cut into townships, squares nominally 6 miles on each side (36 square miles).
- Township lines run east and west. Rows of townships are counted north or south of the base line. Many textbooks call these rows tiers. "Township 2 South" is the second row south of the base line.
- Range lines run north and south. Columns of townships are counted east or west of the principal meridian. "Range 3 East" is the third column east of the meridian.
So "T2S, R3E" (township two south, range three east) names one specific 6-mile square: second row south, third column east.
Because meridians converge as they go north, a grid of perfect squares cannot fit the curved earth. Surveyors run guide meridians and standard parallels every 24 miles to control the error.
Sections and how they are numbered
Each township is divided into 36 sections, each nominally 1 mile square, which is 640 acres. Numbering starts with Section 1 in the northeast corner and runs back and forth (a pattern called boustrophedon, "as the ox plows"):
| West | East | |||||
|---|---|---|---|---|---|---|
| Row 1 | 6 | 5 | 4 | 3 | 2 | 1 |
| Row 2 | 7 | 8 | 9 | 10 | 11 | 12 |
| Row 3 | 18 | 17 | 16 | 15 | 14 | 13 |
| Row 4 | 19 | 20 | 21 | 22 | 23 | 24 |
| Row 5 | 30 | 29 | 28 | 27 | 26 | 25 |
| Row 6 | 31 | 32 | 33 | 34 | 35 | 36 |
Useful landmarks: 1 is northeast, 6 is northwest, 31 is southwest, and 36 is southeast. Going straight down the east column: 1, 12, 13, 24, 25, 36.
Government lots
Not every section comes out as a clean 640-acre square. BLM handles the leftovers with lots: numbered parcels that are not regular fractional parts (aliquot parts) of a section. Lots may contain more or less than 40 acres but are still a subdivision unit of the section. They show up in two situations:
- Along the north and west sides of a township, where the excess or deficiency from the earth's curvature and survey error is placed.
- Along navigable bodies of water, such as a meandered river or lake, because the water's bed is not divided into aliquot parts.
These are commonly called government lots, and a description might read "Government Lot 3, Section 8," followed by the township and range.
Exam tips
- Meridian = north-south line; base line = east-west line.
- Townships (rows, or tiers) are counted N or S; ranges are counted E or W.
- Township = 6 x 6 miles = 36 sections. Section = 1 square mile = 640 acres.
- Section 1 is NE, section 36 is SE.