The Key West Historic District (also known as Old Town of the City of Key West) is a U.S. historic district (designated as such on March 11, 1971) located in Key West, Florida. It encompasses approximately 4,000 acres (16 km²), bounded by White, Angela, Windsor, Passover, Thomas and Whitehead Streets, and the Gulf of Mexico. It contains 187 historic buildings and one structure.

Key West Historic District
U.S. National Register of Historic Places
U.S. Historic district
Overview of part of the Key West Historic District from atop the La Concha
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Location	Key West, Florida
Coordinates	24°33′13″N 81°47′43″W / 24.55351°N 81.79526°W / 24.55351; -81.79526
Area	4,000 acres (1,600 ha)
Built	1822
NRHP reference No.	71000245 (original) 83001430 (increase)
Significant dates
Added to NRHP	March 11, 1971
Boundary increase	February 24, 1983

On February 24, 1983, the district was expanded to 5,400 acres (22 km²), bounded by Emma, Whitehead, White, and South Streets, Mallory Square, and the Atlantic Ocean, to contain 2485 historic buildings and four structures.

Old Town is the name given to the historic district of the island of Key West, Florida. It is roughly the western half of the island. It is also where the central business district and majority of tourist attractions are located.