This sub-series consists of materials related to local airports, including correspondence, memorandums, articles, and maps. The majority of materials in the sub-series document development at the Ontario International Airport, including files on noise control, foreign trade zone applications, and airport terminals and facilities.

This sub-series consists of files related to district road developments and projects, including Interstate and local road improvements. Materials in the sub-series include correspondence, memorandums, articles, and reports.

This sub-series consists of materials related to military bases surrounding the district, including March Air Force Base, George Air Force Base, and the Naval Weapons Fleet Analysis Center. Files in the sub-series include correspondence, memorandums, notes and articles that document services and military uses at these bases, base realignment recommendations, and proposed developments at military facilities.