Washington (state) for the southernmost section where the border follows the Snake River. Oregon is to the south, with the Columbia River forming the western part and the 46th parallel forming the eastern part of the Oregon-Washington border. To the west of Washington lies the Pacific Ocean. Its northern border lies mostly along the 49th parallel, and then via marine boundaries through the Strait of Georgia, Haro Strait, and Strait of Juan de Fuca, with the Canadian province of British Columbia to the north. Washington is part of a region known as the Pacific Northwest, a term which always includes Washington and
Washington State Route 510 also became (I-5) in 1968. SR 510 between I-5 and Pacific Avenue was reconstructed and widened in late 2003, with the addition of a roundabout at the Pacific Avenue intersection. The I-5 interchange will be replaced in 2020 with a diverging diamond interchange that began construction in October 2018. The interchange will be the first diverging diamond constructed in Washington and is estimated to cost $72 million, with funding provided by the state legislature's 2015 Connecting Washington package. State Route 510 Alternate, also known as the Yelm Loop, is a partially completed bypass of Yelm. The first, section opened to