The Florida Keys' iconic highway was built on the bones of a failed railroad.

History · Published 20 October 2026 Swipe more like this →

In short: The Overseas Highway, a 113-mile marvel connecting the Florida Keys to the mainland, owes its existence to a catastrophic hurricane. When a 1935 storm crippled the Overseas Railroad, the state purchased the abandoned rail bed for $640,000, transforming iron tracks into a modern coastal road for automobiles.

The highway's origins trace back to the 1920s, when the Miami Motor Club sought to open the Keys to tourism. The initial route, State Road 4A, was a disjointed patchwork of roads and ferry services that relied on rickety wooden bridges. By the early 1930s, the limitations of this system were clear, prompting the state to seek federal funding. During the Great Depression, the Federal Emergency Relief Administration employed hundreds of World War I veterans to construct the roadway, a project that ended in tragedy when the 1935 Labor Day hurricane struck. Over 400 people died, including many veterans, leading to a Congressional investigation into the project's management.

Following the storm, the Florida East Coast Railway could not afford to repair its tracks, allowing the state to acquire the infrastructure. Engineers retrofitted the surviving railroad bridges with concrete surfaces, creating a more direct and stable route. This connected highway officially opened on March 29, 1938, becoming the southernmost segment of U.S. Route 1. During World War II, the U.S. Navy pushed for further improvements to ensure better access to the Naval Air Station on Boca Chica Key, leading to a realignment that shortened the route by 17 miles and was completed in 1944.

Today, the highway serves as a vital artery, with mile markers providing a unique addressing system that indicates location and distance from Key West. While the original bridges have been replaced by modern structures, several historic spans remain as pedestrian and fishing sites, listed on the National Register of Historic Places since 1979. Current efforts, such as the Florida Keys Overseas Heritage Trail, aim to preserve the remaining Flagler Railroad bridges, ensuring that the remnants of the original rail line continue to serve the public as a multi-use path.

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