evidence: Venezuela administers a number of Caribbean islands and archipelagos, among which are Margarita Island, La Blanquilla, La Tortuga, Los Roques, and Los Monjes. Since the early 19th century Venezuela has claimed jurisdiction over Guyanese territory west of the Essequibo River totaling some 53,000 square miles (137,000 square km)—nearly two-thirds of the land area of Guyana. Venezuela also has had a long dispute with Colombia over the delimitation of maritime boundaries in the Gulf of Venezuela and around the archipelago of Los Monjes.