The County Highway Department office is located at the County Highway Department Complex, 1809 7th Street NE, Beulah. The County Highway Superintendent is appointed by the County Commission to serve as the department head for these operations.

Mission: To provide and maintain an efficient, safe, environmentally sensitive, and cost effective county transportation system to effectively meet citizen's needs for personal mobility and movement of goods consistent with the importance of transportation.

The Mercer County Highway Department is responsible for the efficient planning, design, construction, and maintenance of highways and bridges on the County highway system as well as bridges on the township system. Mercer County has more than 650 miles of County highways. There are also more than 50 bridges greater than 20 feet in length and many smaller drainage structures in Mercer County.