AMP: 0 Location: S-286 and S-205, Gallatin Cty Reassurance shield as S-286 begins. AMP: 1 Location: S-286 and Carpenter Rd, Gallatin Cty A mile into the route, we’ll enter the Missouri Headwaters State Park. This is where the Madison, Gallatin, and Jefferson Rivers combine to form the mighty Missouri. AMP: 3 Location: S-286 and Trident Rd, Gallatin Cty … Continue reading Montana Secondary Highway 286, S-205 to Trident