The mission of the Pennington County Highway Department is to construct and maintain a system of highways and bridges, facilitating the safe and efficient movement of people and goods throughout the county.

Pennington County Highway Department is responsible for the survey, design, construction, inspection, maintenance and repair of the Pennington County road and bridges system which consists of 258.35 County State Aid Highway Miles, 1.69 County State Aid Municipal Miles, 397.17 County Road Miles and 100 Bridges.

This department is also responsible for the county's signage, which includes all highway regulatory safety and informational signing