Lake Okeechobee, (IPA: /okɪtʃobi/) locally referred to as Lake O or The Big Lake is a freshwater lake in the U.S. state of Florida. It is the second-largest freshwater lake wholly within the continental United States, second only to Lake Michigan and the largest in the southern United States. Okeechobee covers 730 square miles (1,890 km²) and is relatively shallow, with an average depth of only 9 feet (3 m). The lake covers land in Glades, Okeechobee, Martin, Palm Beach, and Hendry counties. Maps of Florida show that all five of these counties meet at a point near the center of the lake.
The name Okeechobee comes from the Hitchiti words "oki" (water) and "chubi" (big), and literally means "big water". It was also previously called Macaco and Mayaimi, the latter being the origin of the name of the city Miami, Florida by way of the Miami River.
The floor of the lake is a limestone basin, and the lake varies in depth from 1 to 12 feet (0.3 to 4 m), its water being somewhat murky from nutrient-enriched runoff from surrounding farmlands. The surface is above sea level, and the lake is enclosed by a 20-foot (6 m) high dike built by the U.S. Army Corps of Engineers after a hurricane in 1928 breached the old dike, flooding surrounding communities and claiming thousands of lives. There are several inflows, including Taylor Creek and the Kissimmee River, and several small outlets, such as the Miami River, the New River on the east, and the Caloosahatchee River (via the Caloosahatchee Canal and Lake Hicpochee) on the southwest.