Puget Sound region and settled the Puget Sound area. The first non-indigenous settlement was New Market (now known as Tumwater) in 1846. In 1853 Washington Territory was formed from part of Oregon Territory. In 1888 the Northern Pacific railroad line reached Puget Sound, linking the region to eastern states. For a long period Tacoma was noted for its large smelters where gold, silver, copper and lead ores were treated. Seattle was the primary port for trade with Alaska and the rest of the country and for a time possessed a large shipbuilding industry. The region around eastern Puget Sound developed heavy industry during
Puget Sound Central Basin. Puget Sound's sills, a kind of submarine terminal moraine, separate the basins from one another, and Puget Sound from the Strait of Juan de Fuca. Three sills are particularly significant—the one at Admiralty Inlet which checks the flow of water between the Strait of Juan de Fuca and Puget Sound, the one at the entrance to Hood Canal (about below the surface), and the one at the Tacoma Narrows (about ). Other sills that present less of a barrier include the ones at Blake Island, Agate Pass, Rich Passage, and Hammersley Inlet. The depth of the basins is