Master Title Plats
Master Title Plats are large-scale graphic representations of current Federal ownership, agency jurisdiction, and rights reserved to the federal government on private land. Federal ownership of the subsurface mineral estate and acquisitions, exchanges, and sales involving federal lands are also identified. Rights granted or permitted to private parties for such commercial activities as road rights-of-way, power lines, pipelines, and communication sites are symbolized on the Master Title Plats. Private lands are identified with the original patent number reflecting ownership transfer out of federal jurisdiction. Supplemental Plats are created for portions of those Master Title Plats where detail is so dense that a larger cartographic scale is required.
Use Plats have been created when necessary to show location and identification of oil and gas leases, geothermal leases, and other fluid and solid mineral activities. Gradually the use plats are being combined with the Master Title Plats and new Master Title Use Plats are created. It is important to note that mining claims are not shown on any of the Plats.
Additionally, there are one or more Master Title Plats for each township in Oregon and Washington, except where the township falls completely within an Indian reservation or within a National Park. Land status information for these areas' exclusions is to be found with the appropriate agency, either the Bureau of Indian Affairs or the National Park Service.
Master Title Plats and Historical Indices replaced Plat Books and Tract Books in the 1960s.