Tacoma is a mid-sized urban port city in and the county seat of Pierce County, Washington, United States. The city is on Washington's Puget Sound, 32 miles southwest of Seattle, 31 miles northeast of the state capital, Olympia, and 58 miles northwest of Mount Rainier National Park. The population was 198,397, according to the 2010 census. Tacoma is the second-largest city in the Puget Sound area and the third largest in the state. Tacoma also serves as the center of business activity for the South Sound region, which has a population of around 1 million.Tacoma adopted its name after the nearby Mount Rainier, originally called Takhoma or Tahoma. It is locally known as the "City of Destiny" because the area was chosen to be the western terminus of the Northern Pacific Railroad in the late 19th century. The decision of the railroad was influenced by Tacoma's neighboring deep-water harbor, Commencement Bay.