AMP: 167 Location: US-12 and US-87, Musselshell Cty Reassurance shield as 87 joins 12. The two routes will concur into downtown Roundup. AMP: 168 Location: US-12 and 7th St, Roundup A mile or so later, we’ll enter Roundup. AMP: 169 Location: 1st Ave and Main St, Roundup As we enter Roundup, we’ll need to turn … Continue reading U.S. Route 12, US-87 to US-87