Colón is a sea port city on the Caribbean Sea coast of Panama. It is near the Atlantic entrance to the Panama Canal. The city is the capital of Panama's Colón Province and has traditionally been known as Panama's second city. Colón was traditionally located entirely on Manzanillo Island, surrounded by Limon Bay, Manzanillo Bay and Folks River. Since the abolition of the Canal Zone, the city's limits have been redefined to include the former Canal Zone towns of Cristobal, Rainbow City, Margarita and Coco Solo, as well as the former US military base of Fort Gulick.