A small key, located in lower Biscayne Bay, on the south side of Caesar Creek.

Gerdes, in his "Reconnaissance of the Florida Reefs and all the Keys" (1849) states: "Black Caesar's Key is an island, small, between Old Rhodes Key & Elliot's Key (Old Rhodes being nearest to N. of Key Largo); the opening on both sides is called Black Caesar's Creek." An environmental impact statement published in 1978 by the Biscayne National Monument contains a map which shows Caesar Key here.

Probably named for William Meigs, who came to the Biscayne Bay area from Philadelphia in 1891.