More info: Pigeon Key is a small 5 acre island which lies 2 miles west of Marathon beneath what is now called the Old Seven Mile Bridge. In the early 1900s, Pigeon Island served as a base camp for workers during construction of the original Seven Mile Bridge, the awe-inspiring centerpiece of Henry Flagler's Key West Extension of the Florida East Coast Railroad.
A museum on the island details the construction of the Key West Extension, commonly called the Oversea Railway because its track stretched more than 100 miles out into open water. More than 400 workers lived in the railroad village on Pigeon Key, which had a post office, commissary and one-room school, during the Seven Mile Bridge's construction from 1908 to 1912. Following its completion, maintenance crews continued living on the island.