Fort Jefferson formed part of a chain of forts stretching north from Fort Washington at Cincinnati to Fort Deposit at Waterville during the Indian War of 1790-1795, when the United States built forts in contested territory. It was the fourth fort in this chain of fortifications, generally placed within a hard day's march of the others. Constructed in October 1791 under the orders of General Arthur St. Clair, governor of the Northwest Territory, it arose as tribes of the region were attacking the encroaching American population moving north of the Ohio River. That month, St. Clair set out on a mission to punish the tribes, and on October 12 he ordered his forces to build the fort near a supply of fresh water and named it after Secretary of State Thomas Jefferson.