Lake Worth, city, Palm Beach County, southeastern Florida, on Lake Worth (a lagoon); incorporated as a city 1929. It is a tourist and retirement center, with sand beaches and a long fishing pier. The community was developed (1910-12) by a land company, which gave away free lots to attract residents. It is named for General William J. Worth, a major figure in the Second Seminole War. Population 27,048 (1980); 28,564 (1990); 35,133 (2000).