U.S. Route 730 (US 730) is an east–west United States Highway, of which all but 6.08 miles of its 41.78 miles (9.78 of 67.24 km) are within the state of Oregon. The highway starts in rural Morrow County in Eastern Oregon at an interchange with Interstate 84 (I-84) and US 30, located east of the city of Boardman. US 730 travels east along the Columbia River as a continuation of Columbia River Highway No. 2 into Umatilla County, intersecting I-82 and US 395 in the city of Umatilla. US 730 and US 395 form a short concurrency within the city before the highways part, with US 730 continuing northeast into Washington. The highway travels through rural Walla Walla County and ends at an intersection with US 12 south of Wallula. US 730 was created with the original United States Highways on November 11, 1926, traveling on the existing Columbia River Highway, established in 1917, from US 30 in Umatilla to US 410 south of Wallula. The Washington section of US 730 was added to the state highway system in 1923 as a branch of State Road 3, later becoming a branch of Primary State Highway 3 (PSH 3) in 1937. The highway was concurrent with US 395 from 1937 until 1985, traveling from Cold Springs Junction to US 410. US 30 was moved to a new route bypassing Umatilla and Irrigon in 1946, allowing for US 730 to be extended southwest to Boardman, later to an interchange with I-84.