AMP: 39 Location: US-287 and MT-21, Lewis & Clark Cty Reassurance shield after MT-21. AMP: 39 Location: US-287 and MT-21, Lewis & Clark Cty 19 miles to junction Montana 200. AMP: 39 Location: Main St and Warden Rd, Augusta, Lewis & Clark Cty Less than a mile later, we’ll enter unincorporated Augusta. AMP: 38 Location: Main St and Manix … Continue reading U.S. Route 287, MT-21 to S-435