The Sanborn Fire Insurance Maps of Oregon are an extensive collection of detailed maps of 178 towns and cities in Oregon prepared for the primary use of insurance companies. The bulk of the maps were prepared in the 1880s through 1920s. The maps depict both business and residential areas and provide detailed information about the location and type of construction of structures. Most of the maps are at a scale of 1 inch = 50 feet.

The collection includes maps of Portland, Astoria, Bend, Corvallis, Eugene, Medford, and Salem as well as numerous smaller towns and villages. Of special note are maps of the 1905 Lewis and Clark Centennial Exposition grounds in Portland.

All types of structures are represented, including homes, apartments, and boarding houses; churches; schools, courthouses, community halls, parks, playgrounds, and other public facilities; warehouses, factories, mills, dryers, canneries, and creameries; retail stores, banks, and other businesses; and garages, barns, and sheds. The maps provide detailed information about lumber and saw mills and log ponds. Information about streets and railroads as well as the water system and fire department for each municipality are provided on the maps.

The Sanborn Maps indicate the type of construction of each structure, whether it is wood, brick, stone, or a combination; the size of the structure and number of floors; and the heating source.

This collection includes original color maps; b/w microfiche of maps; and a booklet summarizing the history and development of the Sanborn Map and a color key to the map symbols. Encapsulation of some sheets was begun in the late 1980s. Only a small percentage of the maps have been encapsulated. Maps of larger towns and cities (Portland, Eugene, Salem, Klamath Falls, and Medford) are in bound volumes; some of the volumes have been completely or partially dis-bound.