How many Mary Mcmahon census records do you have?

We have 7966 US Census records for Mary Mcmahon, from 1900 to 1950, across 50 states and DC.

What's in a Mary Mcmahon 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 Mcmahon'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 Mcmahon census records free?

Yes. All Mary Mcmahon 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 Mcmahon?

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

How do I find Mary Mcmahon 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 Mcmahon?

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 Mcmahon — US Census Records & Model Tree

We found 7966 free census records for Mary Mcmahon across 6 census years (1900–1950), in 50 states and DC and 811 counties. Each record includes our Model Tree — the same person linked across decades using machine learning, with per-link confidence scores.

Mary Mcmahon Census Records by State & County

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Showing of 7966 records for Mary Mcmahon US Census, ranked by Model Tree richness

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Year	Name	Age	Location	Birthplace	Occupation	Relation
1940	Mary R. Mcmahon	23	Essex-County, Massachusetts	Massachusetts	Saleslady	Daughter
1940	Mary Mcmahon	37	Washington-County, Pennsylvania	Pennsylvania	Clerk	Daughter
1940	Mary Mcmahon	36	Clackamas-County, Oregon	Oregon	Bookkeeper	Daughter
1930	Mary E. Mcmahon		Norfolk, Massachusetts	Ireland	—	Wife
1920	Mary Mcmahon		New York, New York	Ireland	—	Head
1930	Mary E Mcmahon		Sequoyah, Oklahoma	Arkansas	—	Wife
1920	Mary Mcmahon		New York, New York	Ireland	Washing	Head
1920	Mary Mcmahon		Bronx, New York	Ireland	—	Head
1930	Mary Mcmahon		New York, New York	Ireland	None	Head
1920	Mary Mcmahon		Philadelphia, Pennsylvania	Ireland	None	Wife
1930	Mary Mcmahon		Elkhart, Indiana	Indiana	None	Wife
1940	Mary Mcmahon	67	Madison-County, Illinois	Illinois	—	Wife
1940	Mary Mcmahon	72	Bronx-County, New York	Ireland	—	Head
1940	Mary Mcmahon	67	Queens-County, New York	Ireland	—	Head
1940	Mary Mcmahon	66	Cook-County, Illinois	Illinois	—	Head
1920	Mary J Mcmahon		Merrimack, New Hampshire	New Hampshire	—	Daughter
1910	Mary Mcmahon		Providence, Rhode Island	Rhode Island	Weaver	Daughter
1930	Mary Mcmahon		Middlesex, Massachusetts	Massachusetts	—	Daughter
1930	Mary P. Mcmahon		Henrico, Virginia	Virginia	None	Daughter
1910	Mary Mcmahon		Erie, New York	Ireland	—	Wife
1910	Mary Mcmahon		Essex, New Jersey	New York	—	Wife
1910	Mary Mcmahon		Kings, New York	Ireland	—	Wife
1930	Mary H. Mcmahon		Salem, New Jersey	New Jersey	—	Daughter
1910	Mary Mcmahon		Luzerne, Pennsylvania	Scotland	None	Wife
1910	Mary Mcmahon		Philadelphia, Pennsylvania	Pennsylvania	—	Wife
1920	Mary Mcmahon		Hamilton, Illinois	Illinois	—	Daughter
1910	Mary E Mcmahon		Middlesex, Massachusetts	Massachusetts	—	Daughter
1900	Mary Mcmahon	39	Oakland, Michigan	Michigan	—	Wife
1940	Mary Mcmahon	57	Middlesex-County, New Jersey	New Jersey	—	Wife
1930	Mary G. Mcmahon		Dubuque, Iowa	Iowa	—	Daughter

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About Mary Mcmahon US Census Records & Model Tree

We've indexed 7966 free, proprietary US Census records for Mary Mcmahon across 1900–1950, covering 50 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, 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 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 7966 US Census records for Mary Mcmahon, from 1900 to 1950, across 50 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 Mcmahon'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 Mcmahon 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 Mcmahon records from the 1900 through 1950 US Federal Census, across 50 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.

Other Mcmahon US Census Records

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