This subseries chiefly consists of oversize maps, plats, charts, plans, drawings, cross-sections, and blueprints of NPIC facilities. Also present are a small number of plans for proposed reservoirs, ditches, and enlargements that were not built, as well as maps of the NPIC system, the surrounding area, and subdivision plans and filings. Some maps show property ownership. Materials are grouped by system feature or subdivision name and housed by size but listed alphabetically. Most materials are 24x36 inches or smaller, though Drawer 5 contains full-size folders; two extra-large maps are rolled onto tubes. Folders and tubes are listed alphabetically by title, all of which were imposed by the archivist. Many files are restricted because of post-2004 materials or the presence of detailed documents related to facilities.