Mercer Island Genealogy Database
Mercer Island genealogy research combines city records from the 1960 incorporation date with the deep King County archives that hold records going back to 1852. Birth, death, marriage, land, court, and naturalization records tied to Mercer Island families are found through King County offices and the Washington State Digital Archives. This guide covers where to find what you need, whether you are searching for records from the late 1800s or the last few decades.
Mercer Island Overview
Mercer Island City Records
The City of Mercer Island website connects researchers to the City Clerk, who maintains city council minutes, ordinances, resolutions, and public records. Mercer Island incorporated in 1960 from unincorporated King County. Pre-incorporation records for the island are held by King County archives. The clerk's office processes public records requests for municipal documents from 1960 to the present. If you need to find zoning decisions, council actions, or city government records from the past six-plus decades, start here.
The city website provides the gateway to municipal records from 1960 onward.
The City Clerk's office is accessible through the city's online portal for public records requests covering the incorporated period from 1960 to the present.
For records before 1960, you need to go to King County. The island was part of unincorporated King County before that date, so all historical vital records, property records, and court documents from that era are in the county system. King County was created from Thurston County on December 22, 1852. The King County Auditor holds birth and death records from 1891 to 1907 and marriage records from 1853. The King County Clerk has divorce records from 1886, probate records from 1891, and court records from 1890.
King County Genealogy Records
King County is the key repository for pre-incorporation Mercer Island records and for all county-level vital records. The County Auditor's Office is at 516 Third Ave., Room W-1033, Seattle, WA 98104, phone 206-296-1655. The Superior Court Clerk's Office is at King County Courthouse, 516 3rd Ave., Room E609, Seattle, WA 98104-2386, phone 206-296-9300. The King County Recorder's Office at 500 Fourth Ave, Room 311, Seattle, holds plats, surveys, and deeds.
The Washington State Digital Archives holds King County Auditor birth records from 1891 to 1907. This collection has nearly 20,000 records searchable by parents' names, the child's name, soundex, gender, and year range. The records were transcribed and proofread by the South King County Genealogical Society Extractions Committee. Searching by parents' names, especially the mother's maiden name, tends to work best.
The Washington State Digital Archives collection offers digitized birth records from this region.
These digitized King County birth records are searchable at no charge through the Washington State Digital Archives and cover the pre-state registration period for all communities in King County including Mercer Island.
Marriage Records for Mercer Island Research
Marriage records are often central to genealogy work. King County has one of the most complete sets of marriage records in Washington State. The Washington State Digital Archives holds King County marriage certificates from 1855 to 2017. This is an enormous collection covering over 150 years of marriages in King County. You can search by either spouse's name and filter by marriage year range. The database also supports Soundex searching if you are unsure of exact spelling.
Prior to December 6, 2012, the records use the terms "Groom" and "Bride." After that date, the database uses "Person A" and "Person B" to reflect changes in Washington marriage law. For more information, contact the Washington State Archives Puget Sound Regional Branch at (425) 564-3940 or psbrancharchives@sos.wa.gov.
King County marriage records from the mid-1800s through 2017 are accessible through this digitized collection.
This collection of King County marriage records at the Washington State Digital Archives is searchable online and free to use, covering marriages from early territorial settlement through recent history.
FamilySearch and Online Resources
The FamilySearch Wiki page for King County, Washington provides a comprehensive overview of available records. It lists King County Auditor birth records from 1891 to 1907, marriage records from 1855 to 2017, recorder plats and surveys from 1870 to the present, military records, historical school district registers and censuses from 1890 to 1936, naturalization records at the County Clerk from 1906 to 1920, and probate records from 1854 to 1927 at FamilySearch with index and images.
FamilySearch lists local research facilities for King County including the King County Archives, Seattle Public Library, King County Library System, and numerous FamilySearch Centers. The King County Library System serves Mercer Island and the surrounding communities. The main library branch there may hold local newspaper collections and reference materials useful for genealogy.
The RootsWeb Washington State Genealogical Society King County guide provides direct contact information for the primary county offices holding genealogical records. For the Recorder's Office, the website at www.kingcounty.gov/business/Recorders.aspx has marriage and deed records on microfilm and microfiche.
Note: There is no known history of courthouse disasters in King County, so records tend to be well-preserved from early dates forward.
Records After 1907
For birth and death records after July 1, 1907, the Washington State Department of Health Center for Health Statistics handles requests. The office is at 101 Israel Road SE, Tumwater, WA 98501, with an info line at (360) 236-4300. Birth and death certificates cost $20.00 for events from July 1, 1907 onward.
Marriage records from January 1, 1968 to four months before the present can be ordered through the Center for Health Statistics. For recent certificates from the last four months, contact the King County Auditor where the license was filed. For marriages before January 1, 1968, use the county auditor's records. Divorce records from 1968 onward are available through the state. Before 1968, contact the King County Superior Court Clerk directly.
The Washington State Library's death vital records guide notes that the Seattle-King County Health Department holds death records from 1891 to 1907. The City of Seattle death returns cover 1881 to 1907. These early records are held in the State Library's NW Microfilm collection. For Mercer Island residents who died before the city was incorporated, you would look in the King County and Seattle-area collections at the State Library or Washington State Archives Puget Sound Regional Branch.
King County Genealogy Records
Mercer Island is in King County. All county-level genealogy records for Mercer Island, including records from before the 1960 incorporation, are held through King County offices. For a full overview of King County's genealogy collections, archives, and research contacts, visit the county records page.
Nearby Cities
These qualifying cities are near Mercer Island. Each has its own genealogy records page.