How many John Hennessey census records do you have?

We have 2828 US Census records for John Hennessey, from 1900 to 1950, across 49 states and DC.

What's in a John Hennessey census record?

You'll see John's age, birthplace, occupation, and relationship to the head of household — plus everyone else who lived in the same home. For 1940 and 1950 records, you can also view the original handwritten census page.

How do I use census records for family research?

Census records are a snapshot of a family every 10 years. You can follow John Hennessey's household over time — see when children appear, when people move states, and who's living together. YourRoots connects census data with Tree Matching and AI tools so you can build out your tree faster.

Are John Hennessey census records free?

Yes. All John Hennessey census records on YourRoots are free to search and view — no subscription required. We built our own index from the original federal census images.

Which census years and states cover John Hennessey?

We have John Hennessey records from the 1900 through 1950 US Federal Census, across 49 states and DC. Use the year and state filters to narrow your results.

How do I find John Hennessey in the census?

Start by narrowing the year and state. If you know an approximate birth year, use the age column to match — census age minus the census year gives you a birth year estimate. Household members, birthplace, and occupation help confirm you have the right person.

What is the Model Tree for John Hennessey?

The Model Tree is YourRoots' unique feature that links a person across multiple census decades and reconstructs their likely family — parents, siblings, spouse, and children — based on household patterns. It turns isolated records into a connected family network.

Where does the census data come from?

All records originate from the US Federal Census microfilm digitized by NARA (National Archives and Records Administration). YourRoots re-indexed the original page images using modern AI, catching names and details that older transcriptions missed.

John Hennessey — US Census Records & Model Tree

We found 2828 free census records for John Hennessey across 6 census years (1900–1950), in 49 states and DC and 423 counties. Each record includes our Model Tree — the same person linked across decades using machine learning, with per-link confidence scores.

John Hennessey Census Records by State & County

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Showing of 2828 records for John Hennessey US Census, ranked by Model Tree richness

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Year	Name	Age	Location	Birthplace	Occupation	Relation
1940	John Hennessey	21	Providence-County, Rhode Island	Rhode Island	Office Clerk	Son
1940	John Hennessey	25	Hamilton-County, Ohio	Ohio	Cashier	Head
1940	John J. Hennessey	23	Providence-County, Rhode Island	Rhode Island	Battery Hand	Son
1900	John Hennessey	47	New York, New York	Ireland	—	Head
1930	John Hennessey		New York, New York	New York	Attendant	Head
1920	John Hennessey		Blue Earth, Minnesota	Pennsylvania	Tailor	Head
1930	John H Hennessey		Flathead, Montana	Wisconsin	Hotel Keeper	Head
1900	John Hennessey	45	Rice, Minnesota	Illinois	Farmer	Head
1930	John Hennessey		New York, New York	New York	—	Son
1940	John T. Hennessey	18	Suffolk-County, Massachusetts	Irish Free State	Clerk	Son
1940	John Hennessey	17	Westchester-County, New York	New York	—	Son
1940	John Hennessey	12	Cook-County, Illinois	Illinois	—	Son
1940	John Hennessey	15	Kings-County, New York	New York	—	Son
1940	John Hennessey	50	Philadelphia-County, Pennsylvania	Pennsylvania	Stationary Engineer	Head
1930	John Hennessey		Cook, Illinois	Illinois	—	Son
1920	John Hennessey		Lancaster, Nebraska	Illinois	Farmer	Head
1940	John Hennessey	12	Philadelphia-County, Pennsylvania	Pennsylvania	—	Son
1920	John Hennessey		Monroe, New York	New York	Electrician	Son
1940	John F. Hennessey	46	Queens-County, New York	Canada-English	Asst Manager	Head
1940	John Hennessey	23	Middlesex-County, Massachusetts	Massachusetts	860	Son
1930	John J. Hennessey		Ward, North Dakota	Minnesota	Laborer	Son
1940	John Hennessey	20	Linn-County, Iowa	Iowa	News Boy	Son
1940	John J Hennessey	42	Suffolk-County, Massachusetts	Irish Free State	Janitor	Head
1930	John L. Hennessey		Washington, Maryland	Maryland	Farmer	Head
1940	John Hennessey	59	Perry-County, Ohio	Ohio	Sta. Engineer	Head
1910	John Hennessey		Suffolk, Massachusetts	Ireland	Laborer	Head
1940	John Hennessey	45	Will-County, Illinois	Illinois	—	Son
1940	John E. Hennessey	12	Jackson-County, Missouri	Missouri	—	Son
1930	John A Hennessey		Suffolk, Massachusetts	Irish Free State	Fireman	Head
1940	John J. Hennessey	61	Suffolk-County, Massachusetts	Scotland	Steamfitter	Head

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About John Hennessey US Census Records & Model Tree

We've indexed 2828 free, proprietary US Census records for John Hennessey across 1900–1950, covering 49 states and DC: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin.

Each record includes our Model Tree — a longitudinal reconstruction that links the same person across census decades using machine learning (XGBoost record linkage). Every link carries a confidence score: Verified (≥0.99), Confirmed (≥0.95), or Linked (lower confidence). This tells you not just what the census says, but how reliably we've connected records across time.

Every record also shows the full household — who John lived with, their ages, birthplaces, and occupations. For 1940 and 1950 records, you can view the original handwritten census page from the National Archives.

How we build the Model Tree. YourRoots independently indexes US Census records from NARA microfilm and links persons across decades using XGBoost-based record linkage. Each link's confidence is a per-pair match score from the model. Household corroboration (co-residents appearing on the same census pages in multiple years) strengthens the signal. The Model Tree is not a family tree submitted by users — it's reconstructed from the census data itself.

Last updated: July 30, 2026

Frequently Asked Questions

: We have 2828 US Census records for John Hennessey, from 1900 to 1950, across 49 states and DC.
: You'll see John's age, birthplace, occupation, and relationship to the head of household — plus everyone else who lived in the same home. For 1940 and 1950 records, you can also view the original handwritten census page.
: Census records are a snapshot of a family every 10 years. You can follow John Hennessey's household over time — see when children appear, when people move states, and who's living together. YourRoots connects census data with Tree Matching and AI tools so you can build out your tree faster.
: Yes. All John Hennessey census records on YourRoots are free to search and view — no subscription required. We built our own index from the original federal census images.
: We have John Hennessey records from the 1900 through 1950 US Federal Census, across 49 states and DC. Use the year and state filters above to narrow your results.
: Start by narrowing the year and state. If you know an approximate birth year, use the age column to match — census age minus the census year gives you a birth year estimate. Household members, birthplace, and occupation help confirm you have the right person.
: The Model Tree is YourRoots' unique feature that links a person across multiple census decades and reconstructs their likely family — parents, siblings, spouse, and children — based on household patterns. It turns isolated records into a connected family network.
: All records originate from the US Federal Census microfilm digitized by NARA (National Archives and Records Administration). YourRoots re-indexed the original page images using modern AI, catching names and details that older transcriptions missed.

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