The Interstate Highways in Alaska are all owned and maintained by the US state of Alaska. The Alaska Department of Transportation & Public Facilities (DOT&PF) is responsible for the maintenance and operations of the Interstate Highways. The Interstate Highway System in Alaska comprises four highways that cover 1,082.22 miles (1,741.66 km). The longest of these is Interstate A-1 (A-1), at 408.23 miles (656.98 km) long, while the shortest route is A-3, at 148.12 miles (238.38 km) long. All Interstates in Alaska are unsigned and are not generally referred to by their highway numbers.