Fort Campbell is a large post of the United States Army located approximately ten miles northwest of downtown Clarksville, Tennessee. It is the home of several units of the Army but most notably the 101st Airborne Division. It is officially styled as "Fort Campbell, Kentucky", because the post headquarters, the vast majority of the base housing, and its main post office are in Kentucky; however, the majority of the reservation is actually in Tennessee. Fort Campbell is the single largest factor in the Clarksville area's economy.

Changes to the 101st Airborne are intended to make the Army more capable to deal with today's threats. The post is expecting another 2,000 troops, with the addition of another brigade, bringing the total active-duty population of Fort Campbell to around 28,000.

For information on the census-designated place, see: Fort Campbell North, Kentucky