San Diego, California
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and second-largest city in California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. The city is located on the coast of the Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
in Southern California
Southern California is a megaregion, or megapolitan area, in the southern area of the U.S. state of California. Large urban areas include Greater Los Angeles and Greater San Diego. The urban area stretches along the coast from Ventura through the Southland and Inland Empire to San Diego...
, immediately adjacent to the Mexican border. The birthplace of California, San Diego is known for its mild year-round climate, its natural deep-water harbor, and its long association with the U.S.