Grassy Key, Florida, is an island in the middle Florida Keys. It is located on U.S. 1 (or the Overseas Highway), at approximately mile markers 57—60, below the Conch Keys. It has an area of 3.65 km², with a population of 974 as of the census 2000.
It is one of the northernmost islands in a chain of islands that comprises the City of Marathon, Florida. The island or "key"—as the islands are called in parts of Florida—hosts many mom-and-pop-type family resorts - oceanside and bayside, as well as many private residences, although the key itself is sparsely populated in comparison to the original City of Marathon "proper" farther south. The entire key was incorporated into the City of Marathon in 1999.
The Dolphin Research Center is a dolphinarium located in Grassy Key at mile marker 59.
Florida became a state in 1845, but the keys weren’t officially incorporated until 1870 after they were surveyed by Charles F. Smith. According to locals the key was named after an old settler circa 1855, other documents state the key as being named “Ellis Island before 1855.” The early pioneers suffered from clouds of mosquitos and no-see-ums. They lived in thatched roofed houses that were regularly mowed down by hurricanes, and were cut off from civilization because the island was only navigable by boat. The FEC built the railroad in 1908, and it brought some prosperity to the area. It connected the island to civilization and opened up an opportunity for a tourism industry, and ease of moving goods like pineapple, key limes, sponges, charcoal, and shark skins.
Grassy Key’s first postmaster was appointed on August 26, 1908. He was known as Julius W. Taylor from the Crainlyn Post Office. The original name of the island was Crainlyn after the Crain family. The Crain Family were the landholders of Grassy Key before being incorporated into Florida. Julius W Taylor was the first known person to advertise tourism to the Grassy Key area. He advertised to the Jacksonville area stating that ‘if you were suffering from the Jacksonville heat, come to Grassy key where the ocean and Gulf breezes steadily blow’.
In 1925 the first highway was completed with ferry landings to complete the 40-mile gap between the Lower Matcombe keys and Key West. With the addition of the highway running through Grassy Key Ed Neff’s Bonefish Lunchroom was built in 1935 complete with gas pumps to accommodate tourists that could now drive to Key West instead of taking a ferry. This highway was nicknamed the Overseas Highway.