McHenry County is in Northern Illinois, bordering on Wisconsin. It is often considered part of the greater Chicagoland area. It was formed in 1836 from Cook and LaSalle counties and has been its present size since 1839. It was named for Major William McHenry who served in the Illinois Militia during Tecumseh’s War and the Blackhawk War, and later served in the Illinois legislature.
Birth and death records have been kept since 1878, Marriage records, Probate records and Land Records date to the founding of the county. Many of the early records may be found on FamilySearch.org.
Vital Records can be requested from the County Clerk’s office for a small fee. Information is at https://www.mchenrycountyil.gov/county-government/departments-a-i/county-clerk/vital-records
Early records may also be found at the IRAD depository at Northern Illinois University. Additional records available at IRAD include school records and naturalization records.
There is an active Genealogical Society for the County – the McHenry County Illinois Genealogical Society at mcigs.org.
Note: This was originally published in the "County Spotlight" column in the Illinois State Genealogical Society Newsletter (September 2020).