How many William Brennan census records do you have?

We have 5277 US Census records for William Brennan, from 1900 to 1950, across 50 states, DC, and 2 territories.

What's in a William Brennan census record?

You'll see William'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 William Brennan'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 William Brennan census records free?

Yes. All William Brennan 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 William Brennan?

We have William Brennan records from the 1900 through 1950 US Federal Census, across 50 states, DC, and 2 territories. Use the year and state filters to narrow your results.

How do I find William Brennan 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 William Brennan?

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.

William Brennan — US Census Records & Model Tree

We found 5277 free census records for William Brennan across 6 census years (1900–1950), in 50 states, DC, and 2 territories and 580 counties. Each record includes our Model Tree — the same person linked across decades using machine learning, with per-link confidence scores.

William Brennan Census Records by State & County

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Showing of 5277 records for William Brennan US Census, ranked by Model Tree richness

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Year	Name	Age	Location	Birthplace	Occupation	Relation
1930	William Brennan		Schuylkill, Pennsylvania	Pennsylvania	Painter	Son
1930	William J Brennan		Schuylkill, Pennsylvania	Pennsylvania	Laborer	Son
1930	William Brennan		Philadelphia, Pennsylvania	Pennsylvania	Helper	Head
1930	William Brennan		New York, New York	New York	Painter	Son
1940	William Brennan	30	Carbon-County, Pennsylvania	Pennsylvania	Pipe-Fitter	Head
1940	William Brennan	29	Mercer-County, New Jersey	New Jersey	Rodman	Son
1930	William Brennan		Schuylkill, Pennsylvania	Pennsylvania	Laborer	Head
1920	William J. Brennan		Worcester, Massachusetts	Illinois	Machinist	Head
1920	William Brennan		New Castle, Delaware	Ireland	Farming	Head
1940	William Brennan	54	Macoupin-County, Illinois	Missouri	Miner	Head
1910	William Brennan		Suffolk, Massachusetts	Ireland	Laborer	Head
1920	William Brennan		Dauphin, Pennsylvania	Pennsylvania	Helper	Son
1920	William R. Brennan		Kent, Rhode Island	Massachusetts	—	Son
1920	William Brennan		Kings, New York	New York	None	Son
1940	William Brennan	18	Benton-County, Minnesota	Minnesota	50	Son
1930	William Brennan		Cook, Illinois	Illinois	Steamfitter App	Son
1940	William H. Brennan	10	Suffolk-County, Massachusetts	Massachusetts	—	Son
1940	William Brennan	41	St.-Clair-County, Michigan	Michigan	Farmer	Head
1940	William Brennan	34	York-County, Maine	Massachusetts	Gardner	Head
1930	William Brennan		Elk, Pennsylvania	Pennsylvania	—	Son
1940	William Jr. Brennan	11	St.-Clair-County, Michigan	Michigan	—	Son
1940	William Brennan	20	Luzerne-County, Pennsylvania	Pennsylvania	Wire Worker	Son
1940	William Brennan	46	Sanilac-County, Michigan	Michigan	Farmer	Head
1910	William R Brennan		New Castle, Delaware	Delaware	—	Son
1930	William Brennan		Clinton, New York	New York	—	Son
1920	William Brennan		Fillmore, Minnesota	Minnesota	Farmer	Head
1930	William Jr. Brennan		Essex, New Jersey	New Jersey	Salesman	Son
1930	William J Brennan		Essex, Massachusetts	Massachusetts	—	Son
1930	William V. Brennan		Cuyahoga, Ohio	Ohio	Tool-Maker	Head
1930	William Brennan		Essex, Massachusetts	Irish Free State	Stationary Fireman	Head

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About William Brennan US Census Records & Model Tree

We've indexed 5277 free, proprietary US Census records for William Brennan across 1900–1950, covering 50 states, DC, and 2 territories: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Guam, 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, Puerto Rico, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming.

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 William 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 5277 US Census records for William Brennan, from 1900 to 1950, across 50 states, DC, and 2 territories.
: You'll see William'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 William Brennan'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 William Brennan 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 William Brennan records from the 1900 through 1950 US Federal Census, across 50 states, DC, and 2 territories. 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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