Ontario County, New York Genealogy Records

Selected record inventories for Ontario County, their listed years, and where to ask for access.

Selected inventory review: 2026-11-02. Selected catalog metadata extracted from the linked sources. This is not an examination of original records, a complete county holdings audit, or certification of current access. Historical sources are identified in the access note. NYSL newspaper holdings · Historical NYG&B microfilm bibliography

Formed
1789
County seat
Canandaigua
Allegany CountyCayuga CountyChemung CountyGenesee CountyLivingston CountyMonroe CountyOnondaga CountyOrleans CountyOswego CountySchuyler CountySeneca CountySteuben CountyTioga CountyTompkins CountyWayne CountyWyoming CountyYates CountyOntario CountyCayugaGeneseeLivingstonMonroeOrleansSchuylerSenecaTompkinsWayneWyomingOntario
Ontario CountyToday's boundaries · U.S. Census Bureau

Listed record inventories

Selected holdings and indexes for Ontario County, checked against the repository descriptions linked below. Date spans may contain gaps; an index is not a complete set of original records.

Other records

Newspapers and directories

See the repository's descriptions and search options

Repository access note: Selected sources are linked on individual entries. NYSL newspaper dates summarize service-copy microfilm holdings, not a continuous run or the newspaper’s entire publication life; follow the link for exact issues and gaps. Court surveys describe county holdings and may require advance arrangements. Historical NYG&B microfilm listings refer to a collection transferred to NYPL; confirm current availability there. These sources do not promise online images or complete county coverage.

Sources: the catalogs and repository descriptions linked on the entries above. Selected inventories do not establish complete coverage of every record type or online access to original documents. Read the repository access note for source dates and limitations.

Where to find the records

  • Ontario County official website

    Hours, addresses and phone numbers for the county clerk, the surrogate's court and the town or city clerk, and any online record search the county offers.

  • The county clerk

    Deeds and other land records, naturalizations and court records.

  • The surrogate's court

    Wills, estates and guardianships.

  • The town or city clerk

    Births, marriages and deaths registered locally (New York City has its own vital records).

  • The New York State Archives

    In Albany: state records, including the state censuses, and the statewide indexes to births, marriages and deaths outside New York City.

  • New York State Archivesfree

    The state archives in Albany: state censuses, court and military records, and genealogical guides.

  • FamilySearch Catalogfree

    Search by place for "New York, Ontario" to find filmed and digitized records, many viewable free online with a FamilySearch account.

Offices change their hours and access rules; call before you visit.

Boundaries and parent counties

Formed from: Montgomery County

Check the parent county for earlier records: Montgomery County

Later formed partly from Ontario County: Genesee County, Livingston County, Monroe County, Steuben County, Wayne County, Yates County

RichmondKingsSuffolkNew YorkQueensWestchesterOrangeUlsterBerkshire (Mass.)ColumbiaAlbanyClintonDutchessWashingtonMontgomeryOntarioOntarioMontgomerySuffolkUlsterAlbany
Ontario as created in 1789Where its land was the day beforeToday's boundaryBoundaries: Newberry Library, Atlas of Historical County Boundaries

Records stay with the county that created them. If your ancestor lived here before 1789, search the parent county. The Atlas of Historical County Boundaries shows each boundary change.

Research tip

New York took state censuses in years ending in 5 from 1825 to 1875, and in 1892, 1905, 1915 and 1925. Many survive at the county clerk's office and fill gaps between federal censuses.