Distance Measures


4 poles or rods, or 22 yards, or 66 feet, or 100 links, or 1/80 of a mile.


1/100 of a chain, or 0.66 feet, or 7.92 inches.

Statute Mile

5,280 U.S. survey feet, or approximtely 1.6 km. Also 8 furlongs, or 80 chains, or 320 rods, or 1760 yards.


3 miles

Nautical mile

1,852 meters exactly, or approximately 6,076 feet, or approximately 1.15 statute mile. A nautical mile is approximately 1 minute of latitude on the earth's surface.

U.S. Inch

1/39.37 meter exactly, or approximately 2.54 cm, or 3 barley corns

U.S. Survey Foot

12 inches, or 12/39.37 meter exactly, or approximately 30.480061 cm.

International Foot

30.48 cm. exactly.

French Foot

1.06575 U.S. Survey Foot. This measure is encountered in Lousiana land titles.


In old land surveys, same as rod or perch. In railroad usage, the count of telegraph poles along the line. Each railroad had a different standard spacing, typicallly 40 to 1 mile but sometimes 48 or other number depending on terrain and strength of poles available. Additional closer-spaced poles at junctions, bends, etc may be counted.


Count of rail segments along a railroad line. Often 39 ft but other distances may apply. Continuous welded rail has obsoleted this usage.


180/30 French feet (30 toises = 180 French feet), or approximately 6.39 U.S. feet


30 toises, or 180 French feet, or approximately 192 U.S. feet. In rural Louisiana, an arpent is officially 191.994 feet. In urban Louisiana, an arpent is approximately 191.835 feet.

Rod, Perch, Pole

16.5 feet, or 25 links. This unit supposedly was defined in the 16th century as the length of the left feet of the first 16 men out of church on a certain Sunday. More likely it is a traditional unit of measure of Danish and German origins.


40 poles, or 660 feet, or 1/8 mile


330 feet, or 5 chains, so named because public land land surveyors carried 10 talley pins plus one in the ground, and measured with a half-length chain (33 ft). Therefore every 10 half-chains the head chainman ran out of pins and called "out" to signal the rear chainman that it was time to trade places.


approximately 33 inches. It is encountered in the Southwest U.S. where Spanish land boundaries were measured in this unit. Its exact length varies from region to region. In California, a vara is 33 inches. In Texas, a vara is 33-1/3 inches. In Florida, a vara is 33.372 inches.

Area Measures


43,560 square feet, or 4,840 square yards, or 10 square chains, or 1/640 square mile. Note that 10 acres is equivalent to a square 1/8 mile on each side, or one square furlong.


1 square perch, or 272.25 square feet, or 1/160 acre

Square Rood

1/4 acre


10,000 square meters, or approximately 2.47 acres


177.14 acres


4,428.40 acres

Square mile

640 acres


approximately 0.85 acres. It is encountered in the south central U.S. where French land titles were measured in this unit. Its size varies from region to region. In Arkansas and Missouri it is 0.8507 acres. In Mississippi, Alabama, and Florida, it is 0.84625 acres. In Louisiana it is 0.845 acres


Approximately 1 square mile. A section is a unit of the U.S. Public Land Survey System (PLSS), and its size varies according to the local survey. See PLSS article in Wikipedia.