Find Washington County Genealogy
Washington County sits west of Portland in the Tualatin Valley, one of the most populated parts of Oregon. Genealogy research here draws from land records, farm documents, and vital files held at the county seat in Hillsboro. Searching Washington County archives reveals the shift from farm life to tech industry that defines this region today. Records date to 1843, making Washington County one of the original four districts in Oregon and a deep well for family history research.
Washington County Clerk Records
The Washington County government center in Hillsboro holds records that stretch back to 1843. This is one of the oldest record sets in Oregon. Marriage files, deed books, lien records, and assessment rolls are all on file. The clerk's office is the first stop for Washington County genealogy work.
Washington County was named for President George Washington. It was one of the first four districts created when Oregon was still a territory. From 1843 on, the clerk logged land sales, marriages, and court actions. Early deed books show Donation Land Claims filed by settlers who came west on the Oregon Trail. These claims list the settler's name, the date, and the land they chose. For genealogy, a Donation Land Claim is one of the strongest records you can find. It places an ancestor in Washington County at a known date and ties them to a specific piece of ground in the Tualatin Valley.
The property assessment and tax rolls are another strong tool. They list each landowner in Washington County along with the value of their land and buildings. These rolls are annual, so they let you track a family year by year. A gap in the rolls may mean that an ancestor sold their land, moved, or died. Each of these events sends you to a different record type for more detail.
Under ORS Chapter 192, most Washington County records are public. You can visit the office in Hillsboro or request copies by mail.
This image shows the Washington County government portal. It gives access to property records and other files useful for genealogy research in the Hillsboro area and across the county.
Washington County Historical Society
The Washington County Historical Society runs the Washington County Museum in Hillsboro. The museum holds photos, maps, newspapers, and personal papers from across the county's history. For genealogy, these materials add detail that official records miss. A photo of a family farm, a letter from a soldier, or a newspaper clipping about a wedding can bring an ancestor's story to life.
The museum's collection is especially strong on Tualatin Valley agriculture. For more than a hundred years, Washington County was farm country. Wheat, hops, berries, and dairy products drove the local economy. Farm families left records in the form of land deeds, water rights, and crop reports. The Historical Society has gathered many of these into its archive. Researchers can view them by appointment. Church records, school files, and club rosters are also in the collection. Each one can add names and dates to your Washington County family tree.
The Historical Society also hosts talks and events on local history. These can be a good way to meet other researchers and learn about Washington County genealogy sources you might not find on your own.
The image above shows the Washington County Heritage website. It is a useful guide to the museum's collections and events for researchers tracing Washington County ancestry.
Note: The Washington County Museum requires an appointment for access to its genealogy archive, so call or email before you plan a visit.
Tualatin Valley Genealogy Records
The Tualatin Valley is the geographic heart of Washington County. Hillsboro, Beaverton, and Tigard all grew up in this valley. Each town has its own history, and each left records that are useful for genealogy. City directories, newspaper files, church logs, and school records all help trace Washington County families through the decades.
Old newspapers from Hillsboro are a top source. The Hillsboro Argus ran for over a century. Its pages hold birth notes, marriage news, death reports, and legal filings. Every issue is a snapshot of Washington County life at a given moment. Copies are on microfilm at the Hillsboro Public Library and at the Oregon State Archives. A single newspaper mention can confirm a date, a name, or a family link that no other record proves.
Beaverton and Tigard grew fast in the late 1900s as the tech industry moved into Washington County. The so-called Silicon Forest brought thousands of new residents. For recent genealogy, property records, school enrollment files, and city directories from this era can help track families who came to Washington County in the 1970s, 1980s, and 1990s. These records are at the county and at local libraries.
Washington County at State Archives
The Oregon State Archives in Salem holds Washington County records on microfilm. Circuit Court files date from 1843. Probate files, school records, and agricultural economy documents are also in the collection. Because Washington County is one of the oldest in Oregon, its holdings at the State Archives are among the largest and most complete.
Probate files from Washington County are rich in detail. They list heirs, describe farm land, and sometimes include inventories of tools, livestock, and household goods. A probate file from the 1860s might name every child, list every acre, and describe every cow on the farm. That kind of detail can solve mysteries in a Washington County family tree that no other document can. These files are indexed and stored on microfilm at the State Archives.
Circuit Court case files cover a wide range of matters. Land disputes, debt cases, and estate fights all ended up in court. The files hold names, dates, and sworn statements. For Washington County genealogy, these cases can show family ties, business links, and personal disputes that explain why an ancestor made a given choice. Under ORS 192, most court records are open to the public and can be viewed at the State Archives in Salem.
This shows the State Archives listing for Washington County. It includes the record types and date ranges available, which helps you plan a focused research visit.
Washington County Vital Records
Birth and death records in Oregon are held at the state level by the Oregon Health Authority. State birth records start in 1903. Death records also begin in 1903. For Washington County births and deaths before that year, you must turn to church records, cemetery files, and newspaper notices.
Marriage records are at both the county and state level. The Washington County Clerk has marriage files from 1843 to the present. The State Archives holds copies on microfilm. To get a certified copy of a vital record, you can write to the state office or use an online service. Under ORS 192.420, most public records are available on request, though some vital records have limits based on the age of the record and the requester's link to the person named.
Cemetery records in Washington County add another path for genealogy. Historic cemeteries in Hillsboro, Beaverton, and other towns have burial logs that list names, dates, and sometimes family links. Some of these have been transcribed and posted online by local genealogy groups.
Note: Washington County marriage records from before 1860 are sparse, so check church registers and newspaper files for that era as well.
How to Search Washington County
Start with the facts you have. List every name, date, and place you know. Then choose the record type most likely to fill your gaps.
Washington County genealogy covers a huge span of time. Records from the 1840s sit alongside files from the 2000s. The best approach depends on the era you are working in. For ancestors in the 1800s, land records and probate files are your strongest tools. For the 1900s, vital records and census rolls take the lead. For recent decades, property records and newspaper archives are most helpful.
- Check the Washington County Clerk for marriage and deed records
- Visit the Washington County Museum for photos and local papers
- Search the Oregon State Archives for probate and court files
- Review census records online through the National Archives
Online tools can speed up your Washington County research. The State Archives has a searchable catalog. The National Archives has digitized census and military records. Local genealogy groups may have posted indexes of Washington County records on the web. These can save hours of work and help you plan a focused visit to the archives.
Nearby Counties
Washington County borders Multnomah County, Columbia County, Tillamook County, Yamhill County, and Clackamas County. If your ancestors lived near the county line, records may be filed in a neighboring county.