As well as numerous neighbouring islands, Mexican territory includes the more remote Isla Guadalupe and the Islas Revillagigedo in the Pacific. Mexico's total area covers 1,972,550 square kilometers, including approximately 6,000 square kilometers of islands in the Pacific Ocean, Gulf of Mexico, Caribbean Sea, and Gulf of California (see the map.) On its north, Mexico shares a 5000-kilometer border with the United States. The meandering Río Bravo del Norte (known as the Rio Grande in the United States) defines the border from Ciudad Juárez east to the Gulf of Mexico. A series of natural and artificial markers delineate the United States-Mexican border west from Ciudad Juárez to the Pacific Ocean. The Mexico-U.S. boundary is jointly administered by the International Boundary and Water Commission.On its south, Mexico shares an 871 kilometer border with Guatemala and a 251-kilometer border with Belize.