How many William Callahan census records do you have?

We have 4741 US Census records for William Callahan, from 1900 to 1950, across 48 states, DC, and 1 territory.

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

Yes. All William Callahan 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 Callahan?

We have William Callahan records from the 1900 through 1950 US Federal Census, across 48 states, DC, and 1 territory. Use the year and state filters to narrow your results.

How do I find William Callahan 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 Callahan?

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 Callahan — US Census Records & Model Tree

We found 4741 free census records for William Callahan across 6 census years (1900–1950), in 48 states, DC, and 1 territory and 762 counties. Each record includes our Model Tree — the same person linked across decades using machine learning, with per-link confidence scores.

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Showing of 4741 records for William Callahan US Census, ranked by Model Tree richness

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Year	Name	Age	Location	Birthplace	Occupation	Relation
1940	William Callahan	27	Fulton-County, Georgia	Georgia	Landscaper	Son
1930	William Callahan		Middlesex, Massachusetts	Massachusetts	Reporter	Son
1940	William Callahan	28	Erie-County, New York	New York	Repair Man	Son
1940	William Callahan	25	Kings-County, New York	New York	Time Keeper	Head
1940	William Jr. Callahan	22	Cook-County, Illinois	Illinois	File Clerk	Son
1940	William Callahan	63	Montgomery-County, Pennsylvania	Delaware	Laborer	Head
1940	William Callahan	18	Cook-County, Illinois	Michigan	—	Son
1930	William T Callahan		Fulton, Georgia	Alabama	Printer	Head
1900	William D Callahan	2	Lunenburg, Virginia	Virginia	—	Son
1940	William O. Callahan	47	Talbot-County, Maryland	Maryland	Farmer	Head
1910	William Callahan		Hudson, New Jersey	Ireland	Foreman	Head
1900	William M Callahan	48	Campbell, Virginia	Virginia	Farmer	Head
1940	William Callahan	20	Orange-County, New York	New York	—	Son
1940	William Callahan	12	Wayne-County, Michigan	Michigan	—	Son
1910	William Callahan		Merrimack, New Hampshire	New Hampshire	—	Son
1940	William Callahan	16	Freeborn-County, Minnesota	Minnesota	Farmer	Son
1940	William Callahan	17	Jersey-County, Illinois	Illinois	—	Son
1930	William Callahan		Pittsylvania, Virginia	Virginia	Farmer	Head
1920	William J Callahan		Norfolk, Massachusetts	Massachusetts	Laster	Head
1940	William Callahan	45	Bristol-County, Massachusetts	Rhode Island	Designer & Cutter	Head
1940	William Callahan	20	Essex-County, Massachusetts	Massachusetts	Lamp Worker	Son
1940	William Callahan	18	Erie-County, New York	New York	—	Son
1940	William Callahan	15	Bristol-County, Massachusetts	Rhode Island	Bakery Salesman	Son
1910	William Callahan		New Castle, Delaware	Ireland	Watchman	Head
1940	William F. Callahan	24	Middlesex-County, Massachusetts	Massachusetts	Mail Carrier	Son
1920	William J. Callahan		Rockingham, New Hampshire	Ireland	Shoemaker	Son
1940	William Callahan	15	Washington-County, Indiana	Indiana	—	Son
1920	William Callahan		Essex, Massachusetts	Massachusetts	—	Son
1940	William D. Callahan	23	Essex-County, Massachusetts	Massachusetts	Machinist	Son
1920	William Callahan		Middlesex, Massachusetts	Massachusetts	—	Son

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About William Callahan US Census Records & Model Tree

We've indexed 4741 free, proprietary US Census records for William Callahan across 1900–1950, covering 48 states, DC, and 1 territory: Alabama, 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 York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, 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 4741 US Census records for William Callahan, from 1900 to 1950, across 48 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 Callahan'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 Callahan 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 Callahan records from the 1900 through 1950 US Federal Census, across 48 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.

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