Oregon County Assessors' maps are named using specific components based on the area covered by the map. The following sample will assist in explaining how to use the map number to determine the map location. We will use the hypothetical map number 20N40W11AB.pdf. At first glance this map numbers appear to be a collection of random letters and numbers, but these characters actually represent the location of the map within the state.

There are 5 components to the map name 20N40W11AB.pdf.

• “20N” represents the map’s township
• “40W” represents the map’s range
• “11” represents the map’s section
• “A” represents the quarter of the section the map is in
• “B” represents the quarter of the quarter section the map is in.

The length of a map name can help to explain if a map covers a lot of detail for a small area or a large area in less detail. The longer name indicates a map of a small area which contains a lot of detail as is given in the example above. A map with the name “20N40W” covers a large area with little detail. These maps are useful for helping to locate what maps you might be interested in or to look at large tracts of ownership. The following chart outlines the types of maps available on this site and what the name might represent.

How do township, range and section numbers relate to each other?

These map numbers are based on the Public Land Survey System (PLSS). This system, developed early in our nation’s history, uses a grid to describe and catalog the land. This grid is made up of a series of townships, ranges, and sections beginning with townships (horizontal separations) and ranges (vertical separations). Each of these lines are approximately 6 miles apart resulting in 6 mile square divisions. Because of difficulties placing a grid over a round surface and the limitations on early survey equipment, variations do exist. Each Township and Range is further divided into 36 sections. These sections are each approximately 1 mile square.

The following chart provides examples of each map division and how the labels are created. This will help you figure out which map you need.

The numbering for townships and ranges in Oregon begins just west of Portland at the Willamette stone. From this point all townships and ranges are labeled with a number and the corresponding direction letter. The image to the right details the townships and ranges in Oregon as well as the quadrant they belong to. This gives us 4 quadrants. The image to the right shows where the 4 quadrants (NW, NE, SE, SW) are in our state. Some counties drop the direction letter from their map name because all of their maps are in a single quadrant. As an example, Clatsop County’s maps are all in the NW quadrant.
The next component of the map name is the section number. Each township consists of 36 square mile sections that are labeled from 1 to 36. Section 1 begins in the northeast corner and the numbers increase as you move west. The next row of Sections increases as you move east. Exceptions to this numbering occur in a few townships where the size does not permit a full division.
This image shows how quarter section and quarter-quarter sections are labeled. The image represents one section that is divided into 16 squares. Each square can be located using two letters. This system is used on our map. Some counties use numbers instead of letters. If this is the case just substitute an A for a 1, B for a 2, etc…

Many additional resources are available on the web by searching on “township and range” or by looking at the Oregon Department of Revenue’s Map Manual, Chapter 3 for a description of standard taxlot numbers. If you have further questions feel free to email us at OR.MAP@state.or.us.