Fort Dearborn was a United States fort built in 1803 in what is now Chicago, Illinois besides the Chicago River. Specifically, Fort Dearborn was located on the northeast corner of E. Lower Wacker Drive and Lower Michigan Avenue. The fort was named after Henry Dearborn who was the United States Secretary of War at the time under President Thomas Jefferson. The fort that was built in 1803 was destroyed at the Battle for Fort Dearborn during the War of 1812. The fort was reconstructed in 1816. While the fort was decommissioned in 1837, it wasn't until 1871 during the Chicago fire that the entire fort was lost.
The first fort was built on land that was acquired as part of the 1795 treaty of Greenville from the Native Americans. In August of 1812, American forces evacuated Fort Dearborn as it was attacked by local Indians (known as the Fort Dearborn Massacre). The fort was burned and was not well inhabited until 1816 when the fort was rebuilt.
When the fort was rebuilt, soldiers and traders returned to the area. Once rebuilt, the fort became center of control during the Black Hawk War. By 1840 and following its decommission in 1837, the fort had outlived its military use and was demolished in 1857.