Series Title (Agency Series #): Description, Retention (Legal Citation)

Assessment Maps (AT7-002): Documents all tax lot and ownership information. There are four types of maps included in this records series: an annual blue line, the most recently updated computer plot, the digital computer map, and obsolete maps which may show information not included in the digital system. These maps show the size, shape, location, and extent of each real property account in Multnomah County.
Retention: Retain as needed. (MOAR 166-150-0015(7))

Property Classification Memos (AT7-004): Memoranda from Oregon Department of Revenue to the county regarding the tax status of specified properties (often railroad and public utility rights-of-way). Memos show date, legal description of property, action to be taken by the county, and authorization.
Retention: Retain permanently.

Reference Maps (AT7-007): Maps documenting various topographic and political features for use in preparing tax collection maps. Includes railroad maps, state highway maps, other highway maps, General Land Office survey (1851),Metskers maps, Lewis and Dryden City of Portland map (1891), City of Portland boundary and annexation map (1922), City of Portland topographic maps (1991), unrecorded subdivision maps, and related maps.
Retention: Retain as needed. (MOAR 166-150-0015(7))

Road Notes (AT7-003): Records document the official description of county roads. Notes show description of road, road name and number, distance and bearing of road segments, and related road information. This is not a complete collection of road notes for the county.
Retention: Retain permanently. (MOAR 166-150-0205(3))

Subdivision and Partition Plats (AT7-001): Plats are used to help create the title identity to a piece of land that may include subdivision and partition plats. Plats include map and accompanying survey narrative, property description, declaration by owner, and approval by public bodies. The plats are produced by registered professional land surveyors. The original is filed with the county surveyors office.
Retention: Retain permanently. (MOAR 166-150-0205(4))

Unrecorded Surveys (AT7-005) : Records documenting survey of property. Records include drawings of property that have not been recorded. This is not a complete collection of unrecorded surveys in Multnomah County.
Retention: Retain permanently.