AMP: 169 Location: Main St and 8th Ave, Roundup Reassurance shield as 12 joins 87. 87 is the primary posted route here, but the mileposts are consistent with US 12. AMP: 168 Location: Main St and 1st Ave, Roundup A few blocks later, 12/87 will turn to head west. AMP: 168 Location: Main St and … Continue reading U.S. Route 87, US-12 to US-12