Much as been made of the Underground Railroad, the overland network of paths that headed north and was utilized by escaping slaves for decades. But many don’t realize there were other paths to freedom.
One of these was the so-called Saltwater Railroad, which ran south into Florida, following the coastal waterway. Recall that Florida was originally property of Spain and had been serving as a refuge for escaping slaves. Then in 1818 Andrew Jackson, the future president who was a slavery supporter, invaded Spanish Florida to counter the threat from Seminole Indians and any former slaves with malicious intent. This incursion led to the 1819 Adams-Onis Treaty which gave possession of Florida to the U.S. (https://history.state.gov/milestones/1801-1829/florida)
Since Florida was no longer a safe haven, the next preferred destination became the British-controlled Bahamas. Here most of the population was Black, and freemen could own property, marry, and be educated. In 1825 the British government declared that anyone who made it to their territory, regardless of previous status, was free. Then slavery was abolished throughout all British territories in August 1834. Even though this island chain was 154 miles from Florida at its closest point, It was a lot easier than fleeing to Canada and so became the preferred destination for many slaves. Hence the Saltwater Railroad.
For more information, see “The Saltwater Railroad (1821-1861)” by Nicole Campbell at the Blackpast website (https://www.blackpast.org/african-american-history/the-saltwater-railroad-1821-1861/).