An acre is equal to 43,560 square feet or 4,840 square yards of land. This is about equal to about 75 percent of a football field, which is about 48,000 square feet, states The Calculator site. It is also comparable to 16 tennis courts and can hold 150 parked cars.
Traditionally, an acre is 1 furlong long by 4 rods wide, according to Washington Grown. It developed as a standard of measurement comparable to what a yoke of oxen could plow in a single day. Including water, New York City is about 300,000 acres, including its bodies of water, while Greater London is about 388,000 acres.