Caltrans District 8 is one of 12 Caltrans districts and covers approximately 28,650 square miles of land. There are four interstates and 32 state routes totaling 7,200 lane miles within our boundaries. Caltrans District 8 serves the counties of Riverside and San Bernardino as the largest transportation engineering entity in the region by delivering and maintaining safe modes of transportation to all Inland Empire residents.