The Florida Keys Overseas Heritage Trail is a 106-mile (171 km) paved rail trail in development in the Florida Keys, a multi-use bicycle and pedestrian facility. The completed trail will connect Key Largo to Key West, allowing travel through the Keys separate from U.S. Highway 1. It has been made part of the East Coast Greenway, a 3,000-mile (4,800 km) system of trails connecting Maine to Florida, forming its southernmost portion.
The trail incorporates most of the railbed of the former Overseas Railroad built by the Florida East Coast Railway. Rail service began in 1911; the effects of the 1935 Labor Day hurricane ended service that year.
Once fully completed, the trail will be a world-class, multi-use bicycle and pedestrian facility that will traverse the Florida Keys from Key Largo to Key West. The trail will include an integrated system of educational kiosks, roadside picnic areas, scenic overlooks, fishing piers, water access points, and bicycle and jogging paths. The development of the trail will provide a mechanism for the preservation and use of the historic Flagler Railroad Bridges, 23 of which still exist and are mostly intact. Several alternatives exist for trail alignment, including cutting down the 22-foot-wide (6.7 m), 1940s-era roadway to its original 12-foot (3.7 m) spandrel width, or using the 22-foot-wide (6.7 m) roadway as is, particularly in multi-use areas. In all cases, original bridgework will be repaired or rebuilt, and the breaks created during the 1980s and 1990s fishing pier conversion will be reconnected. Where the original roadway no longer exists, the trail will be temporarily cantilevered on the side of the current US 1 highway bridge, until new 12-foot-wide (3.7 m) trail bridge sections can be built. The new sections will be built to match the historical character of the original bridges.
The Florida Keys Overseas Heritage Trail was designated a National Recreation Trail in 2004.