Canyon Highway District No. 4 (CHD4) is one of four Highway Districts in Canyon County. Canyon Highway District boundaries are found primarily in the Northeastern area of Canyon County, surrounding Caldwell. Canyon Highway District was formed in 1981 to maintain public rights-of-way, roads, and bridges in the highway system, within the District's boundaries, excluding state highways and cities.
The Highway District is a political subdivision of the State of Idaho and, according to state law, functions like a corporation. It is a special-purpose district and is not part of the state, city or county governments.