Willamette Meridian

The Willamette Meridian is the principal meridian that governs all PLSS surveys in Oregon and Washington. Established in 1851, it is one of the earliest survey references in the Pacific Northwest and remains the foundation for legal land descriptions across both states. From timber sales in the Cascade Range to rural property transactions in the Willamette Valley, every PLSS description in Oregon and Washington traces back to this meridian.

The Willamette Stone

Unlike most principal meridians, which are defined by geographic coordinates alone, the Willamette Meridian has a physical marker: the Willamette Stone. This stone monument is located in the West Hills above Portland, Oregon, at approximately 45°31' North latitude and 122°44' West longitude. It sits in a small park (Willamette Stone State Heritage Site) in what is now a residential neighborhood — an easy landmark to miss if you do not know to look for it.

Surveyor John B. Preston set the initial point in June 1851 by taking astronomical observations to fix the intersection of the meridian (north-south line) and the Willamette Baseline (east-west line). From this single point, the PLSS grid extends across all of Oregon and Washington, subdividing the land into townships, ranges, and sections.

The original stone marker has been replaced and protected over the years, but the location remains the same. It is one of the few PLSS initial points that you can visit in person.

States Covered

Oregon

Oregon is entirely surveyed under the Willamette Meridian. The state's diverse economy generates PLSS descriptions across multiple industries:

• Timber and forestry: Oregon's timber industry is the largest in the US, and BLM timber sales, national forest boundaries, and private timber holdings are all described using PLSS references. A timber sale notice might reference "Section 22, T8S R3E, Willamette Meridian" to identify a specific harvest unit in the Cascade foothills.
• Agriculture: The Willamette Valley, one of the most productive agricultural regions in the Pacific Northwest, is subdivided under this meridian. Farms growing grass seed, hazelnuts, wine grapes, and hops carry legal descriptions tied to the Willamette grid.
• Real estate: Rural property deeds throughout Oregon use PLSS descriptions. Title companies in counties east of the Cascades — where parcels can be large and ranch-oriented — work with these descriptions daily.
• Public land management: Oregon has vast BLM holdings, particularly in the eastern half of the state. Grazing allotments, mining claims, and recreation permits all reference PLSS locations tied to the Willamette Meridian.

Washington

Washington state is also entirely surveyed under the Willamette Meridian. The same grid extends northward from the Willamette Baseline (which runs east-west through the Portland area), crossing the Columbia River and continuing to the Canadian border.

• Timber and forestry: Washington's timber industry uses PLSS descriptions for national forest management, DNR trust lands, and private harvest operations. The Olympic Peninsula, North Cascades, and eastern Washington forests all fall within the Willamette grid.
• Agriculture: The Palouse region and Columbia Basin agricultural lands are described using Willamette Meridian references. Wheat farming, irrigated crops, and USDA program enrollment all tie to specific quarter sections in the grid.
• Real estate and development: As rural land near growing urban areas (Spokane, Tri-Cities, Bellingham) comes under development pressure, legal land descriptions from PLSS surveys are central to subdivision and permitting processes.

Format Examples

Legal land descriptions referencing the Willamette Meridian follow standard PLSS notation:

• NE 12-4S-2W WM — Northeast Quarter, Section 12, Township 4 South, Range 2 West, Willamette Meridian
• SW 30-8N-5E WM — Southwest Quarter, Section 30, Township 8 North, Range 5 East, Willamette Meridian
• SENE 7-15S-11E WM — Southeast Quarter of the Northeast Quarter, Section 7, Township 15 South, Range 11 East (a 40-acre tract)

The "WM" suffix identifies these descriptions as Willamette Meridian references. Note that townships in Oregon are numbered south from the baseline (T1S, T2S, etc., heading southward from Portland), while townships in Washington are numbered north (T1N, T2N, etc., heading northward). This is a natural consequence of the baseline running through the Portland area — south of the baseline is "South," north is "North."

Survey History

The Willamette Meridian was established during a period of rapid American settlement in the Pacific Northwest. The Oregon Donation Land Claim Act of 1850 promised free land to settlers, and the federal government needed a survey framework to manage these claims. John B. Preston, appointed Surveyor General of Oregon in 1851, made establishing the initial point his first priority.

Survey crews worked outward from the Willamette Stone over the following decades. The densely forested and mountainous terrain of the Cascades and Coast Range made surveying difficult. Some remote areas of eastern Oregon and the Olympic Peninsula were not fully subdivided until the early 20th century.

The original surveys sometimes contain errors — a reality of running lines through thick timber and steep terrain with 19th-century equipment. These survey errors are embedded in the legal record and occasionally surface when modern GPS measurements do not match the platted section boundaries. Understanding this history is important when working with Pacific Northwest PLSS descriptions.

Practical Tips

When working with Willamette Meridian descriptions, keep these points in mind:

1. Confirm the township direction. "T4S" and "T4N" are entirely different locations — one is south of Portland, the other is north. Double-check whether the description specifies North or South.
2. Watch for government lots. Along rivers, lakeshores, and the Pacific coast, standard quarter-section subdivisions give way to irregularly shaped government lots. These lots have specific acreages that differ from the standard 160 or 40 acres.
3. Include the meridian reference. While Oregon and Washington both use only the Willamette Meridian, including "WM" in your descriptions prevents confusion when sharing data with colleagues working in states with multiple meridians.

Converting Willamette Meridian Descriptions

Township America converts Willamette Meridian descriptions from both Oregon and Washington to GPS coordinates. Enter a description like "NE 12-4S-2W WM" to get the latitude and longitude for that parcel. For batch conversion of timber sale data, real estate records, or BLM permit locations, upload a CSV and get coordinates back for every entry.