AMP: 21 Location: US-87 and S-551, Judith Basin Cty Reassurance shield giving MT-3 top billing after S-551. Despite being a route of lower stature, 3 is probably the most important of these three routes, as it is the most direct route to Billings. AMP: 21 Location: US-87 and S-551, Judith Basin Cty 43 miles to US-191. AMP: … Continue reading U.S. Route 87, S-551 to MT-80