The western terminus of Washington State Route 174 is in Leahy, while the eastern terminus is in Wilbur.
SR 174 begins at a junction with SR 17 in Leahy and travels eastward to Grand Coulee, near the Grand Coulee Dam, to intersect SR 155. From Grand Coulee, the roadway travels southeast to end at SR 21 northwest of Wilbur. 
SR 174 begins at an intersection with SR 17 in Leahy, a small community in Douglas County. From Leahy, the highway travels northeastward through grasslands with few farms before turning southeast to intersect its Crown Point spur near the Grand Coulee Dam. From Grand Coulee, the roadway travels southeast to end at SR 21 northwest of Wilbur. 
Western terminus, at-grade intersection Leahy Eastern terminus, at-grade intersection Wilbur 
