How many William Sullivan census records do you have?

We have 19645 US Census records for William Sullivan, from 1900 to 1950, across 50 states, DC, and 1 territory.

What's in a William Sullivan 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 Sullivan'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 Sullivan census records free?

Yes. All William Sullivan 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 Sullivan?

We have William Sullivan records from the 1900 through 1950 US Federal Census, across 50 states, DC, and 1 territory. Use the year and state filters to narrow your results.

How do I find William Sullivan 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 Sullivan?

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 Sullivan — US Census Records & Model Tree

We found 19645 free census records for William Sullivan across 6 census years (1900–1950), in 50 states, DC, and 1 territory and 1656 counties. Each record includes our Model Tree — the same person linked across decades using machine learning, with per-link confidence scores.

William Sullivan Census Records by State & County

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Showing of 19645 records for William Sullivan US Census, ranked by Model Tree richness

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Year	Name	Age	Location	Birthplace	Occupation	Relation
1910	William G Sullivan		Washington, Indiana	Indiana	—	Son
1930	William F. Sullivan		Freeborn, Minnesota	Minnesota	Laborer	Son
1940	William F Sullivan	23	Suffolk-County, Massachusetts	Massachusetts	Battery Man	Son
1930	William J. Sullivan		Philadelphia, Pennsylvania	Pennsylvania	Accountant	Son
1930	William J Jr Sullivan		Middlesex, Massachusetts	Massachusetts	Accountant	Son
1930	William Sullivan		Cuyahoga, Ohio	Ohio	Salesman	Son
1930	William Sullivan		Hamilton, Ohio	Ohio	Laborer	Son
1940	William Jr. Sullivan	31	Hudson-County, New Jersey	New Jersey	Utility Man	Son
1940	William R Sullivan	32	Wyandotte-County, Kansas	Kansas	Time Keeper (Water Line)	Son
1930	William Sullivan		Houghton, Michigan	Michigan	Baker	Son
1940	William Sullivan	31	Dakota-County, Minnesota	Minnesota	Day Laborer	Head
1940	William Sullivan	20	Franklin-County, Ohio	Ohio	Night Mechanic	Son
1940	William Sullivan	37	Providence-County, Rhode Island	Rhode Island	Lab. Technician	Head
1930	William L. Sullivan		Greenville, South Carolina	South Carolina	Laborer	Head
1930	William J. Jr. Sullivan		Essex, New Jersey	New Jersey	Clerk Assistant	Son
1940	William S. (Jr) Sullivan	21	Baltimore-City-County, Maryland	Maryland	—	Son
1930	William A. Sullivan		Lancaster, Nebraska	Nebraska	Collecting	Son
1940	William H. Sullivan	24	San-Francisco-County, California	California	Warehouseman	Head
1940	William Sullivan	45	Tuscaloosa-County, Alabama	Alabama	Farmer	Head
1940	William H. Sullivan	63	Providence-County, Rhode Island	Rhode Island	Dyeing	Head
1940	William F. Sullivan	42	Delaware-County, Pennsylvania	Pennsylvania	Wholesale Salesman	Head
1940	William Sullivan	43	Kings-County, New York	Mass	Salesman	Head
1930	William Sullivan		Cook, Illinois	Michigan	Electrician	Head
1920	William Sullivan		Essex, Massachusetts	Ireland	—	Head
1920	William Sullivan		San Francisco, California	Ireland	None	Head
1940	William E. Sullivan	53	Kanawha-County, West Virginia	West Virginia	Plant Club Rooms	Head
1940	William Sullivan	63	Kings-County, New York	Ireland	Investigator	Head
1940	William H. Sullivan	60	Worcester-County, Massachusetts	Rhode Island	Instructor	Head
1910	William Sullivan		Chatham, Georgia	Georgia	Driver	Head
1930	William H. Sullivan		Russell, Kentucky	Kentucky	Farmer	Head

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About William Sullivan US Census Records & Model Tree

We've indexed 19645 free, proprietary US Census records for William Sullivan across 1900–1950, covering 50 states, DC, and 1 territory: 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, 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 19645 US Census records for William Sullivan, from 1900 to 1950, across 50 states, DC, and 1 territory.
: 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 Sullivan'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 Sullivan 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 Sullivan records from the 1900 through 1950 US Federal Census, across 50 states, DC, and 1 territory. 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.

Other Sullivan US Census Records

Agnes Sullivan Alice Sullivan Anna Sullivan Annie Sullivan Arthur Sullivan Catherine Sullivan Charles Sullivan Cornelius Sullivan Daniel Sullivan Dennis Sullivan Dorothy Sullivan Edward Sullivan Elizabeth Sullivan Ellen Sullivan Eugene Sullivan Florence Sullivan Francis Sullivan Frank Sullivan George Sullivan Helen Sullivan James Sullivan Jeremiah Sullivan John Sullivan Joseph Sullivan Julia Sullivan Katherine Sullivan Margaret Sullivan Mary Sullivan Michael Sullivan Nellie Sullivan Patrick Sullivan Richard Sullivan Robert Sullivan Ruth Sullivan Sarah Sullivan Thomas Sullivan Timothy Sullivan

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