The Fred M. Greguras California Military Places Collection includes ephemera, photographs, documents, maps, and other materials documenting daily life for servicepersons stationed in military places across the state of California in the 19th, 20th, and 21st centuries. The collection also documents the change over time of these military places as elements of the physical built environment, as they were decommissioned or reshaped by new conflicts and concerns.

Greguras’ interest in military history, and more specifically U.S. Marines history in China and the Pacific, led him to collect many items related to military locations in California. United States servicepersons were often stationed at military places in California before serving at locations in Asia and the Pacific. Because of this, the collection also relates to the United States military presence in the Pacific, including China and the Philippines. Conflicts represented include the Spanish-American War, World War I, and World War II, with a focus on the Pacific theatre.

Many materials in the collection document daily life for American military personnel. Ephemera in the collection includes promotional materials for bases, base and regional directories, and commemorative items related to specific conflicts or veterans' services. Yearbooks for specific locations often list the names of officers and enlisted persons. There are also a number of official base newspapers, as well as newsletters created by military servicepersons.

The collection is very visual, with an extensive amount of postcards and many vernacular photographs taken by individuals while serving. In addition, Greguras often visited these sites in the late 20th and 21st centuries to take photographs to document specific sites' contemporary states.

Especially prominent in the collection are materials related to Camp Merritt, Ford Ord, the Presidio of San Francisco, and San Diego area military installations.

Military places are primarily labeled with the names in use during the creation of the items in the folder. Folders are arranged alphabetically by folder title.