how big is 1 acre in square feet
Acre The acre is a unit of land area used in the imperial and US customary systems. It is defined as the area of 1 chain by 1 furlong (66 by 660 feet), which is exactly equal to ​1⁄640 of a square mile, 43,560 square feet, approximately 4,047 m2, or about 40% of a hectare.
United States Forest Service The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands, which encompass 193 million acres (780,000 km2)[3]. Major divisions of the agency include the National Forest System, State and Private Forestry, Business Operations, and the Research and Development branch.[4] Managing approximately 25% of federal lands, it is the only major national land agency that is outside the U.S. Department of the Interior.[5]