How many Mary Monahan census records do you have?

We have 4466 US Census records for Mary Monahan, from 1900 to 1950, across 47 states and DC.

What's in a Mary Monahan census record?

You'll see Mary'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 Mary Monahan'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 Mary Monahan census records free?

Yes. All Mary Monahan 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 Mary Monahan?

We have Mary Monahan records from the 1900 through 1950 US Federal Census, across 47 states and DC. Use the year and state filters to narrow your results.

How do I find Mary Monahan 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 Mary Monahan?

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.

Mary Monahan — US Census Records & Model Tree

We found 4466 free census records for Mary Monahan across 6 census years (1900–1950), in 47 states and DC and 444 counties. Each record includes our Model Tree — the same person linked across decades using machine learning, with per-link confidence scores.

Mary Monahan Census Records by State & County

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Showing of 4466 records for Mary Monahan US Census, ranked by Model Tree richness

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Year	Name	Age	Location	Birthplace	Occupation	Relation
1940	Mary Elizabeth Monahan	40	Essex-County, Massachusetts	Massachusetts	Twister	Daughter
1930	Mary Monahan		Kings, New York	New York	—	Daughter
1940	Mary C. Monahan	34	Douglas-County, Illinois	Illinois	Secretary	Daughter
1940	Mary Monahan	32	New-York-County, New York	New York	Switchboard Opr	Daughter
1940	Mary Monahan	75	Bronx-County, New York	Ireland	—	Head
1920	Mary Monahan		New York, New York	Ireland	—	Wife
1940	Mary Monahan	49	Kings-County, New York	Ireland	—	Wife
1920	Mary Monahan		Suffolk, Massachusetts	Ireland	—	Head
1920	Mary Monahan		New York, New York	Ireland	—	Wife
1940	Mary Monahan	42	Bergen-County, New Jersey	New Jersey	—	Wife
1920	Mary E Monahan		Frederick, Maryland	Indiana	—	Wife
1920	Mary Monahan		New York, New York	Ireland	—	Wife
1920	Mary Monahan		Fairfield, Connecticut	Ireland	—	Wife
1920	Mary Monahan		Providence, Rhode Island	Ireland	None	Head
1940	Mary Monahan	52	Kings-County, New York	Ireland	House Wife	Head
1930	Mary Monahan		San Francisco, California	California	—	Daughter
1940	Mary K. Monahan	14	Leavenworth-County, Kansas	Kansas	—	Daughter
1930	Mary Monahan		Queens, New York	Ireland	—	Head
1930	Mary E. Monahan		Middlesex, Massachusetts	Massachusetts	Clerk	Daughter
1940	Mary D Monahan	34	Suffolk-County, Massachusetts	Massachusetts	—	Wife
1900	Mary Monahan	41	Northumberland, Pennsylvania	Pennsylvania	—	Wife
1930	Mary E. Monahan		Kings, New York	Ireland	None	Wife
1930	Mary M. Monahan		Luzerne, Pennsylvania	Pennsylvania	—	Daughter
1930	Mary Monahan		San Francisco, California	California	None	Daughter
1930	Mary E. Monahan		Worcester, Massachusetts	Massachusetts	Stock Clerk	Daughter
1940	Mary Monahan	14	Suffolk-County, Massachusetts	Massachusetts	—	Daughter
1910	Mary Monahan		Suffolk, Massachusetts	Ireland	—	Wife
1940	Mary C. Monahan	25	Worcester-County, Massachusetts	Massachusetts	General Office Work	Daughter
1910	Mary Monahan		Norfolk, Massachusetts	Ireland	—	Wife
1930	Mary Monahan		Luzerne, Pennsylvania	Pennsylvania	—	Daughter

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About Mary Monahan US Census Records & Model Tree

We've indexed 4466 free, proprietary US Census records for Mary Monahan across 1900–1950, covering 47 states and DC: Alabama, 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 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 Mary 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 4466 US Census records for Mary Monahan, from 1900 to 1950, across 47 states and DC.
: You'll see Mary'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 Mary Monahan'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 Mary Monahan 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 Mary Monahan records from the 1900 through 1950 US Federal Census, across 47 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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