 State Route 27 ( SR 27 ) is a 90 @-@ mile @-@ long ( 145 km ) state highway serving Whitman and Spokane counties , located in the eastern region of the U.S. state of Washington . The highway travels generally north from U.S. Route 195 ( US 195 ) through Pullman , Palouse , Tekoa , and Spokane Valley to SR 290 north of an interchange with Interstate 90 ( I @-@ 90 ) . SR 27 serves the Palouse region as part of the Palouse Scenic Byway and travels between US 195 to the west and US 95 to the east in Idaho , with several auxiliary routes connecting to the two other highways . The highway has been part of the state highway system since 1913 , as a part of the Second Division of the Eastern Route of the Inland Empire Highway between Pullman and Oakesdale that later became a branch of Primary State Highway 3 ( PSH 3 ) , as well as Secondary State Highway 3H ( SSH 3H ) in 1937 . Both highways were combined to form SR 27 during the 1964 highway renumbering and the designation was extended south to the US 195 bypass of Pullman in 1975 and north to SR 290 in 1991 . 
