Caltrans District 8 is one of 12 Caltrans districts and covers approximately 28,650 square miles of land. There are four inte ... rstates 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. read more