Located just south of U.S. Highway 1 near the west end of Key Vaca.

Gerdes, in his "Reconnaissance of the Florida Reefs and All the Keys" (1849) states: "The two Ids. S. of the west point of Key Vaca are names Boot Ids. The 1861 Bache Coast Survey has Boot Key. Boot Key on a survey map drawn by Charles Smith in 1873. A map published in Simpson's " In Lower Florida Wilds" (1920) shows Boot Key.

A field report written for the U.S. Coast & Geodetic Survey in 1935-36 states: "The name Boot Key is well established. Authorities fail to agree on the limits of the keys. Authority 1 (Charles L. Pinder of Key West) shows the whole group as the Boot Keys, Authority 3 (Allan Parrish of Marathon) states that the west group is known as Boot Key and the east group as Boot Key Mangrove. Most local authorities put them into one group as the Boot Keys. It is recommended that they be designated as East Boot Keys east of Sister Creek and West Boot keys west of the Creek." The west group was joined to Key Vaca by a bridge in 1959.