Washington, or the State of Washington as it is formally known, is the westernmost state in the US Pacific Northwest. In order to separate it from the nation’s capital, which is also named for George Washington, the first American president, it is frequently referred to as Washington state[a]. Washington shares borders with the Canadian province of British Columbia to the north, Oregon to the south, Idaho to the east, and the Pacific Ocean to the west. The western portion of the Washington Territory, which the British Empire had given up in the Oregon Treaty of 1846, was used to create the state. In 1889, it became the 42nd state to enter the Union. Seattle is the most populated city, and Olympia serves as the state capital.