King County Genealogy Records

King County holds some of the richest genealogy collections in Washington State, covering births, deaths, marriages, probate files, and court records dating back to the 1850s. Whether you are tracing family lines in Seattle, Bellevue, Kent, or any of the county's many communities, this guide points you to the key sources you need. The Washington State Digital Archives alone holds nearly 20,000 King County birth records and over 150 years of marriage data. Start your King County ancestor search with the resources below.

King County Vital Records and Archives

King County was formed from Thurston County on December 22, 1852. It is the most populous county in Washington, and its genealogy records reflect that scale. The County Auditor holds birth and death records from 1891 to 1907, plus marriage records going back to 1853. The County Clerk holds divorce records from 1886, probate records from 1891, and court records from 1890. These original records are mostly held at or transferred to the Washington State Archives Puget Sound Regional Branch.

The Puget Sound Regional Branch of the Washington State Archives serves King County researchers. You can contact them at (425) 564-3940 or email psbrancharchives@sos.wa.gov. They hold the original county auditor registers and other archival materials that have been transferred from King County offices over the years. For post-1907 vital records, contact the Washington State Department of Health.

Note: The King County Recorder's Office at 500 Fourth Avenue, Room 311, Seattle holds marriage and deed records on microfilm and microfiche. Their website at kingcounty.gov/business/Recorders provides access details.

King County Records in the Digital Archives

The Washington State Digital Archives has digitized and indexed large sets of King County genealogy records. Two of the most used collections are the birth register and the marriage records set. Both are free to search online and include scanned images of the original documents.

The King County Auditor birth records, 1891-1907 contain 19,663 entries. The database was transcribed by the South King County Genealogical Society Extractions Committee. You can search by mother's name, father's name, or the child's name. The mother's last name in these records reflects her maiden name, so keep that in mind when searching. Soundex search is also available to help with spelling variations.

The King County marriage records, 1855-2017 cover more than 150 years of marriages in the county. The database allows searches by groom, bride, or either party's name, with a year range filter. Prior to December 6, 2012, the records use the terms Groom and Bride. After that date, they use Person A and Person B to reflect updated marriage law in Washington. This collection is one of the most comprehensive local marriage databases available for any county in the state.

The Digital Archives also holds King County Historical School Districts, Registers and Censuses, 1890-1936, and King County Clerk Naturalization Records, 1906-1920. School district registers can help you confirm family residence in a specific neighborhood and track children through multiple census years.

The Washington State Archives also holds King County Military Records through the Recorder's office. Veterans who served and settled in King County may appear in discharge records that can supplement a family history.

Lead-in: The Washington State Digital Archives King County birth records database holds 19,663 indexed and imaged entries from the county auditor's register.

These birth records cover the period when the county auditor was responsible for local vital registration, before the state took over that function in 1907.

King County Marriage and Death Records

Marriage records are among the most useful tools in King County genealogy research. The county auditor held these records from the earliest days of county formation. The King County marriage records in the Digital Archives span 1855 to 2017. That range covers territorial marriages, early statehood, and most of the twentieth century. The Recorder's office holds additional microfilm and microfiche copies of marriage and deed records.

Death records in King County present more complexity than most counties. The state library guide lists both the King County Auditor death records from 1891 to 1907 and the Seattle Municipal Health Department death records from 1881 to 1907. The City of Seattle had its own death return system running as early as 1881, which predates the county auditor register. If you are searching for a Seattle death in the 1880s, check both the city and county sources. The State Library holds these early death registers in its NW Microfilm collection, available through interlibrary loan.

Lead-in: The King County Recorder's Office holds marriage records on microfilm going back to early county history.

The Recorder's office at 500 Fourth Avenue in Seattle provides access to these historical marriage and land records for researchers.

Probate, Court, and Land Records

The King County Clerk holds probate records from 1891 and court records from 1890. Probate files are especially valuable in genealogy research because they often name heirs, list assets, and document family relationships in detail. The FamilySearch collection Washington, King County Probate Records, 1854-1927 is available to search online. These records were filmed before some originals deteriorated, making the FamilySearch images a key resource.

King County Clerk Naturalization Records, 1906-1920, are listed in the Digital Archives and the FamilySearch wiki. These records show immigrants who took their oath of citizenship in King County Superior Court. They often include birthplace, age, date of arrival, and the names of witnesses. For King County researchers with immigrant ancestors, these can fill major gaps left by other record types.

Land records for King County date back to the early territorial period. The County Recorder held plats and surveys from 1870 onward. These records help establish when an ancestor arrived in the county, where they settled, and how property moved through families across generations.

Note: The King County Archives, Seattle Public Library, and King County Library System are all listed in the FamilySearch wiki as local research facilities worth contacting directly.

King County Genealogy Research Resources

The FamilySearch wiki for King County is a good starting point. It lists specific record sets, date ranges, and links to online databases. King County was created in 1852 from Thurston County. It was originally named after Vice President Rufus King, then renamed in 2005 to honor Dr. Martin Luther King, Jr. Knowing this history matters when you search older county indexes that may use older county name variants.

Several FamilySearch Centers operate in King County and can give you free access to Ancestry databases and other subscription resources. Contact FamilySearch directly to locate the nearest center to you.

Lead-in: The King County marriage records database at the Digital Archives covers over 150 years of marriage certificates from 1855 through 2017.

Searching the marriage database by either party's name with a year range filter helps narrow results quickly in this large collection.

The RootsWeb guide for Washington State Genealogical Society provides direct contact information for the main King County offices. The King County Auditor is at 516 Third Ave., Room W-1033, Seattle, WA 98104, phone (206) 296-1655. The Superior Court Clerk is at Room E609 of the same building, phone (206) 296-9300.

Cities in King County

King County covers a large area with many incorporated cities and communities. Each of these places has its own history reflected in the county's genealogy records.

Nearby Counties

These counties border King County. If your ancestors lived near the county line, records may cross into neighboring jurisdictions.