Cudjoe Key is a census-designated place and unincorporated community in Monroe County, Florida, United States, on an island of the same name in the lower Florida Keys. As of the 2020 census, the CDP had a population of 2,019, up from 1,763 in 2010.

Monroe County is a county in the state of Florida. As of the 2020 census, the population was 82,874. Its county seat is Key West. Monroe County includes the islands of the Florida Keys and comprises the Key West-Key Largo Micropolitan Statistical Area. Over 99.9% of the county's population lives on the Florida Keys. The mainland, which is part of the Everglades, comprises 87% of the county's land area and is virtually uninhabited with only 17 people recorded in the 2020 census.