AMP: 49 Location: US 12 and Lane Ave, East Helena Reassurance shield after 518 as we head out of East Helena AMP: 55 Location: US-12 and S-284, Jefferson Cty A few miles later, we’ll enter Jefferson County and approach S-284 AMP: 55 Location: US 12 and S-284, Jefferson Cty Turn left for 284. 284 heads … Continue reading U.S. Route 12, S-518 to S-284