美國國道
Each highway is assigned a "Route" (officially "State Highway Route") number in the . Most of these are numbered in a statewide system, and are known as "State Route X" (abbreviated "SR X"). United States Numbered Highways are labeled "US X", and Interstate Highways are "Interstate X". Under the code, the state assigns a unique "Route X" to each highway, and does not differentiate between state, US, or Interstate highways.