Fitchburg was an Estill county community near KY 975 northeast of Irvine. It was established in 1868 with the construction of the massive Fitchburg or Red River Iron Furnace, an 80 foot high sandstone structure that is still standing and is operated by the U.S. Forest Service as an historic site. It was the last, and largest, charcoal iron smelting furnace built in the U.S. The furnace and town were named for the furnace's designer, Fred Fitch, and manager, Frank Fitch. The Fitchburg post office opened in 1870 and closed in 1955.