The Columbia River (known as Wimahl or Big River to the Chinook-speaking natives who live on its lowermost reaches) is the largest river in the Pacific Northwest region of North America. It is name after the Columbia Rediviva, the first ship from the western world known to have traveled up the river. It stretches from the Canadian province of British Columbia through the U.S. state of Washington, forming much of the border between Washington and Oregon before emptying into the Pacific Ocean. The river is 1,243 miles (2,000 km) long, and its drainage basin is 258,000 square miles (670,000 km²).