Fairfax is a city in Linn County, Iowa, United States. The population was 889 at the 2000 census; a special census in 2005 counted 1,662 residents. It is part of the Cedar Rapids Metropolitan Statistical Area.
Fairfax is located at 41°55′11″N 91°46′49″W / 41.91972°N 91.78028°W / 41.91972; -91.78028 (41.919714, -91.780295). It is located along U.S. Route 151 about 7 miles (11 km) southwest of downtown Cedar Rapids.
According to the United States Census Bureau, the city has a total area of 1.4 square miles (3.5 km²), all of it land.