Benton County Genealogy Records

Benton County genealogy records are held at the County Courthouse in Prosser and through the Washington State Digital Archives, covering birth, death, marriage, land, probate, and court records from the county's founding in 1905. The Tri-Cities area, which includes Kennewick and Richland, has a dense population that generated significant records over the past century. Whether you are looking for early 20th-century vital records or more recent genealogical documents, Benton County offers strong online and in-person research options.

Benton County Genealogy at the Digital Archives

The Washington State Digital Archives hosts a wide range of Benton County collections, many available with both index and images at no charge. The county was formed on March 8, 1905, from Klickitat and Yakima counties, so records start from that year. Benton County is one of the more extensively digitized counties in eastern Washington, with multiple collections available online.

The Benton County Auditor Birth Returns, 1905-1907 collection includes an index and images of births filed with the County Auditor from the county's creation through the start of statewide registration. A companion collection, the Benton County Auditor Birth Register, 1905-1907, covers the same period. Since Benton County was only created in 1905, these collections represent essentially the full pre-state-registration period for this county.

For marriage records, the Benton County Auditor Marriage Certificates, 1905-1995 collection provides broad coverage with index and images. Additional marriage-related records include the Marriage Affidavits, 1909-1939, the Marriage License Applications, 1939-1949, 1952-1953, and 1977-1980, and the Marriage Records, 1987-Present collection for ongoing access. These collections together provide a nearly continuous record of marriages in Benton County from its founding to the present.

Land records are also digitized. The Benton County Auditor Plats and Surveys, 1906-2023, and Recorded Land Records, 1938-2023, both include index and images. These are valuable for tracing property ownership across generations and confirming where ancestors lived. The Dental Certificates, 1905-1983 and Professional License Records, 1992-2023 collections, while less commonly used, can help identify specific individuals who worked in licensed professions in Benton County.

Note: For records not yet digitized, contact the Washington State Archives Central Regional Branch in Ellensburg, which serves Benton County and holds physical records transferred from local agencies.

Benton County Auditor Online Document Search

The Benton County Auditor's online document search application (EagleWeb) provides access to recorded documents from January 1972 to the present. The index is updated regularly. This tool is useful for genealogists researching land transactions, liens, and other recorded documents from the past 50-plus years.

The Kennewick Office is located at 7122 W Okanogan Pl, Suite E120, Kennewick, WA, and can be reached at (509) 736-2727. Office hours are 8:30 a.m. to 4:30 p.m., Monday through Friday. Due to privacy concerns, the Auditor's Office may limit published information for some documents to the index only. Images viewed online are unofficial copies. Official certified copies require a visit to the Auditor's office or a mail request.

Copy fees at the Benton County Auditor's office are $1.00 per page for uncertified copies. Certified copies cost $3.00 for the first page and $1.00 for each additional page per document. Mail requests must include the Auditor's File Number and a return address sent to the Benton County Auditor Recording Department at the Kennewick address.

The Benton County Courthouse is located in Prosser, the county seat, while many auditor services are handled through the Kennewick office. If you are unsure which office to contact, call (509) 736-2727 for guidance. The FamilySearch wiki for Benton County provides a helpful overview of what records exist and where to find them.

Central Regional Archives for Benton County

The Washington State Archives Central Regional Branch is located on the campus of Central Washington University in Ellensburg. The branch serves Benton, Chelan, Douglas, Franklin, Grant, Kittitas, Klickitat, Okanogan, and Yakima counties. For Benton County genealogy research, this is the primary physical archive for records not yet digitized.

The Central Regional Branch holds genealogical records including birth and death records from the turn of the 19th century, marriage records from approximately 1867-1997, naturalization records, probate records, pre-statehood county censuses, and schoolchildren censuses from roughly 1890-1932. Completeness varies by county, but branch staff can help identify what Benton County records are in custody and how to access them.

In-person research is available Wednesday through Friday by appointment only. The branch is closed for in-person visits Monday and Tuesday, but phone and email requests are welcome those days. Contact the branch at (509) 963-2136 or CEBranchArchives@sos.wa.gov. Researchers traveling from outside Ellensburg should make advance arrangements to confirm record availability before making the trip.

Tri-City Genealogical Society and Local Resources

The Tri-City Genealogical Society is located in Richland at PO Box 1410, 1314 Jadwin Ave, Richland, WA 99352-1410. The society serves Benton County and the broader Tri-Cities area. Local genealogical societies often maintain unique collections including family histories, cemetery records, and local obituaries that supplement what government archives hold. Contacting the society is a good step for any researcher with deep roots in the Kennewick, Richland, or Pasco area.

The East Benton County Historical Society and Museum, located at 205 West Keewaydin Drive, Kennewick, WA 99336 (phone: 509-582-7704), collects and preserves the history of eastern Benton County. Their collections may include photographs, manuscripts, business records, and personal papers of local families. The Reach Museum at 1943 Columbia Park Trail, Richland, WA 99353 (phone: 509-943-4100) holds historical collections related to Native American history, pioneer settlement, and the Hanford nuclear site, which significantly shaped the region's population in the mid-20th century.

The Hanford nuclear reservation's construction during World War II and the post-war years drew workers and their families from across the country, resulting in a diverse genealogical record base for the Tri-Cities area. If your ancestor arrived in Benton County in the 1940s or 1950s, the local historical society and the Reach Museum may hold records that complement official government sources.

Note: Eastern Benton County is part of the Tri-City Metropolitan Area, and residents near the confluence of the Columbia, Snake, and Yakima rivers may have records in Benton, Franklin, or Walla Walla counties depending on jurisdiction.

Searching Benton County Ancestry Records

Benton County's records started in 1905, which means the oldest genealogical documents in the county go back roughly 120 years. For families with deeper Washington roots, check neighboring Yakima and Klickitat counties, which were the source counties when Benton was created. Marriage records as early as 1867 may exist at the Central Regional Archives for those predecessor jurisdictions.

The Washington State Library's genealogy research guide lists databases and resources for statewide family history research that can complement what is available locally. Census records from 1900, 1910, and 1920 through 1940 are available through FamilySearch and Ancestry.com for Benton County residents. These are especially useful for confirming household compositions and identifying children, parents, and other relatives.

When searching online indexes, keep in mind that older records were often handwritten, and transcription errors in names are common. If a search returns no results, try alternate spellings or use Soundex. The digital archives Soundex option is particularly helpful for surnames with multiple common spellings, such as Schmidt versus Smith, or for immigrant families whose names were anglicized at some point.

Land records at the Benton County Auditor's EagleWeb portal go back to 1972. For earlier land transactions, the physical records at the Central Regional Archives or at the county courthouse in Prosser will be needed. The County Clerk maintains court records, probate files, and divorce decrees that can be key genealogy sources, particularly for understanding family structures and property transfers across generations.

Statewide Washington genealogy resources complement Benton County's local holdings, especially for records from the broader Central Washington region.

Cities in Benton County

Benton County includes the major cities of Kennewick and Richland, both part of the Tri-Cities metropolitan area. Both cities have dedicated genealogy research pages on this site.

Other communities in Benton County include Prosser, West Richland, and Benton City. All genealogy research for these communities routes through the Benton County Courthouse and the Washington State Digital Archives.

Nearby Counties

Benton County is bordered by Franklin, Yakima, Klickitat, and Walla Walla counties. If your ancestor lived near a county line or if records are not found in Benton County, check these neighboring jurisdictions.