AMP: 9 Location: SH-87 and MT-87, Fremont Cty Welcome to Idaho! Multistate Highway 87 is a quick connector for traffic from Ennis heading to Idaho that wish to bypass West Yellowstone. AMP: 9 Location: SH-87 and MT-87, Fremont Cty 9 miles to the southern terminus of Idaho 87 at US 20. AMP: 3 Location: SH-87 … Continue reading Idaho State Highway 87, MT-87/MT State Line to US-20