The Billies Bay Wilderness is part of Ocala National Forest. The 3,092-acre (13 km sq) wilderness was established on September 28, 1984. The mostly marshy and swampy nature of the area is indicated by the word 'bay' as part of the name, since this is a Floridian term for swamp. It contributes to the headwaters of Alexander Springs Creek in the nearby Alexander Springs Wilderness.
Plants in the area include red maple, bay, sweet gum, cabbage palm, scrub oak, Palmetto, gallberry, longleaf, loblolly pine, slash and sand pine.