State Highway 1 (SH-1) is a state highway in Boundary County, in the U.S. state of Idaho. It extends 11.185 miles (18.00 km) from U.S. Route 95 (US-95) east of Copeland, north to British Columbia Highway 21 (BC 21) in Porthill. The route serves as a connector between Bonners Ferry, via US-95 south, Porthill, and Creston, BC. The highway is one of two border crossings from Idaho into British Columbia. The other crossing is at the US-95/BC 95 in Eastport. The highway is also known for being the only state highway in Boundary County, the two other highways are US-95 and US-2. The highway is also part of the International Selkirk Loop, the only international scenic byway in North America.