AMP: 130 Location: SH-21 and SH-75, Stanley Reassurance shield as 21 begins. 21 heads 130 miles from here to Boise and intersects no other state highways. AMP: 130 Location: SH-21 and SH-75, Stanley 21 is a restricted truck route between Lowman and Idaho City. AMP: 127 Location: SH-21 and Iron Creek Rd, Custer Cty Reassurance … Continue reading Idaho State Highway 21, SH-75 to I-84/US-20/US-26/US-30