The Pacific Squadron, established 1821, was part of the United States Navy squadron stationed in the Pacific Ocean in the 19th and early 20th centuries. Initially with no United States ports in the Pacific, they operated out of Naval storeships which provided naval supplies like powder and ammunition and purchased fresh supplies of food, wood and water from local ports of call in California, Hawaiian Islands (called the Sandwich Islands then) and ports and harbors on the Pacific Coast. The Pacific Squadron was instrumental in the capture of Alta California in the Mexican–American War of 1846 to 1848.