Whole-Acre Reference / Sheet 05
40 Acres = 1,742,400 sq ft
Forty acres, the PLSS quarter-quarter section. The historic Reconstruction-era homestead allotment from Sherman's Special Field Order No. 15 of January 1865. The math is exact: 40 multiplied by 43,560 equals 1,742,400 square feet. As a square: 1,320 feet on a side, exactly one quarter of a mile.
Square Feet
1,742,400
Square Metres
161,874
Hectares
16.187
Derivation: 40 acres × 43,560 sq ft per acre = 1,742,400 sq ft, exactly. As a square: 1,320 ft per side (one quarter mile, 20 chains).
Sheet 02 · The PLSS Grid
Where 40 acres comes from
The 40-acre quarter-quarter section is one of the most important units in American land history. It comes from the US Public Land Survey System (PLSS), which the Land Ordinance of 1785 established to organise the territory ceded by Britain at the end of the Revolutionary War. The PLSS divided unsurveyed federal land into townships of 6 miles by 6 miles (36 square miles), with each township containing 36 sections, each section being one square mile (640 acres). The section divides into quarter sections of 160 acres (the standard Homestead Act parcel), each quarter section divides into quarter-quarter sections of 40 acres, and each quarter-quarter divides into 10-acre and smaller fractional units for the densest land descriptions.
The 40-acre size took on additional historical weight after January 16, 1865, when General William Tecumseh Sherman issued Special Field Order No. 15. The order set aside the coastal lowlands from Charleston, South Carolina, southward through the Sea Islands and inland to the St Johns River in Florida for settlement by formerly enslaved families. The order specified that each family would receive up to 40 acres of arable land, with the army providing surplus mules from the war effort. Approximately 40,000 freed people settled on roughly 400,000 acres of confiscated Confederate plantation land between January and September 1865. President Andrew Johnson's Amnesty Proclamation of May 1865 began returning the land to the original Confederate owners, and by autumn 1865 most of the freed-people settlers had been forcibly removed.
The phrase "forty acres and a mule" entered American political vocabulary as shorthand for the unfulfilled promise of post-Reconstruction land redistribution. It has remained a touchstone reference in discussions of African-American economic policy ever since, used in writing by W. E. B. Du Bois, in the title of Spike Lee's film production company (40 Acres and a Mule Filmworks, founded 1979), and in contemporary reparations policy proposals.
For working agriculture, the 40-acre size has practical roots. A team of two horses or two mules in 19th-century plowing technology could work approximately one acre per day with a single-bottom moldboard plow. A 40-acre field could be plowed in about 40 working days, or roughly 6 weeks of spring plowing, which fit within the available time between snowmelt and planting. The same 40 acres could be planted in about 8 to 12 days with a single horse-drawn corn planter or grain drill, and harvested in roughly 30 to 40 days with a horse-drawn binder or reaper. The economics of mid-19th-century mixed-grain and corn farming in the Midwest converged on 40 acres as the practical maximum that one farming family could manage without hired help during the peak labour periods of plowing, planting, and harvest.
The Homestead Act of 1862 used the larger 160-acre quarter-section as the standard claim, but the legislation also permitted smaller claims at the quarter-quarter section (40 acres) for areas with limited water access or rough terrain. Many homestead claims in the arid West, in the wooded mountain regions of the Appalachians, and in the rocky interior of the Pacific Northwest were filed at 40 acres rather than 160. Total Homestead Act claims between 1862 and 1986 (when the act was finally repealed) totaled approximately 270 million acres, making it one of the largest land-redistribution programmes in human history despite its many limitations.