Fort Dearborn was a United States fort built in 1803 beside the Chicago River, in what is now Chicago, Illinois. It was constructed by troops under Captain John Whistler and named in honor of Henry Dearborn, then United States Secretary of War. The original fort was destroyed following the Battle of Fort Dearborn during the War of 1812, and a second fort was constructed on the same site in 1816. By 1837, the fort had been de-commissioned.