AMP: 4 Location: S-518 and US-12, East Helena No reassurance shield as Secondary 518 begins. 518 is a quick spur from East Helena down to I-15 in Montana City. AMP: 0 Location: S-518 and I-15, Montana City, Jefferson Cty Four miles later, we’ll approach I-15. AMP: 0 Location: S-518 and I-15, Montana City, Jefferson Cty … Continue reading Montana Secondary Highway 518, US-12/US-287 to I-15/S-282