San Joaquin is the third-largest city in the US state of Peninsula, located about halfway between La Paz and Santa Helena. The city is located on the eastern coast of the state, on the Gulf of California, and is the location of a major tourist and service industry. San Joaquin is also a large auxiliary port for La Paz, of which it is the northern anchor of the La Paz-San Joaquin urban conglomeration, a region of nearly four million in southern Peninsula. San Joaquin proper has a population of about 475,000 and is part of a 1,000,000 person metropolitan area.