How many James Mcmahon census records do you have?

We have 5638 US Census records for James Mcmahon, from 1900 to 1950, across 49 states, DC, and 1 territory.

What's in a James Mcmahon census record?

You'll see James'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 James 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 James Mcmahon census records free?

Yes. All James 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 James Mcmahon?

We have James Mcmahon records from the 1900 through 1950 US Federal Census, across 49 states, DC, and 1 territory. Use the year and state filters to narrow your results.

How do I find James 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 James 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.

James Mcmahon — US Census Records & Model Tree

We found 5638 free census records for James Mcmahon across 6 census years (1900–1950), in 49 states, DC, and 1 territory and 789 counties. Each record includes our Model Tree — the same person linked across decades using machine learning, with per-link confidence scores.

James Mcmahon Census Records by State & County

Records per state:

Census Record Search

First Name

Middle Name

Last Name (Required)

Census Year

State

Birth Year

Year Range

Birthplace

Age From

Age To

Exact match: Name Location Year

Alternate First Names (comma-separated)

Alternate Last Names (comma-separated)

County

Sex

Marital Status

Race

Relationship to Head

Occupation

Census Page ID

Family Members (in same household)

Search Records

Showing of 5638 records for James Mcmahon US Census, ranked by Model Tree richness

No records match your filters.

Year	Name	Age	Location	Birthplace	Occupation	Relation
1940	James Mcmahon	25	Hudson-County, New Jersey	New Jersey	Teacher	Son
1930	James Mcmahon		New York, New York	New York	Chauffeur	Son
1940	James William Mcmahon	24	Cuyahoga-County, Ohio	Ohio	—	Son
1940	James R. Mcmahon	36	Richland-County, South Carolina	South Carolina	Truck Driver	Head
1940	James T. Mcmahon	29	Middlesex-County, Massachusetts	Massachusetts	Salesman	Son
1940	James Jr Mcmahon	24	Westchester-County, New York	New York	Clerk	Son
1940	James Mcmahon	39	Washington-County, Pennsylvania	Scotland	Postal Clerk	Head
1930	James D Mcmahon		Jackson, Missouri	Missouri	Farmer	Head
1940	James Mcmahon	37	Natrona-County, Wyoming	Wyoming	—	Son
1940	James Mcmahon	30	Bronx-County, New York	New York	Clerk	Son
1920	James Mcmahon		Philadelphia, Pennsylvania	Ireland	Iron Worker	Head
1930	James Mcmahon		New York, New York	New York	Retired	Head
1940	James Mcmahon	65	Brooke-County, West Virginia	Scotland	Sub Sta Operator	Head
1940	James Mcmahon	67	Kings-County, New York	Ireland	—	Head
1930	James Mcmahon		Richmond, New York	Ireland	Labor	Head
1940	James S. (X) Mcmahon	62	Richland-County, South Carolina	Georgia	Nightwatchman	Head
1940	James L. Mcmahon	67	Mccracken-County, Kentucky	Indiana	—	Head
1910	James Mcmahon		Merrimack, New Hampshire	Ireland	Section Man	Son
1940	James F. Mcmahon	48	Middlesex-County, Massachusetts	Massachusetts	Mixing-Foreman	Head
1940	James Mcmahon	23	Middlesex-County, Massachusetts	Massachusetts	Belt Man	Son
1930	James Mcmahon		Kings, New York	New York	Janitor	Head
1940	James M. Mcmahon	17	Middlesex-County, Massachusetts	Massachusetts	—	Son
1940	James R. Jr. Mcmahon	28	Chester-County, Pennsylvania	Pennsylvania	Garage Mechanic	Son
1930	James Mcmahon		Suffolk, Massachusetts	Massachusetts	Bookbinder	Son
1940	James J. Mcmahon	40	Middlesex-County, Massachusetts	Massachusetts	Laborer	Head
1940	James M. Mcmahon	48	Erie-County, New York	New York	Freight Cashier	Head
1930	James Mcmahon		New York, New York	New York	Shipping Clerk	Head
1910	James Mcmahon		Kings, New York	Ireland	Labour	Head
1940	James Mcmahon	10	New-York-County, New York	New York	—	Son
1930	James A. Mcmahon		Suffolk, Massachusetts	Massachusetts	None	Son

Load More James Mcmahon Census Records

About James Mcmahon US Census Records & Model Tree

We've indexed 5638 free, proprietary US Census records for James Mcmahon across 1900–1950, covering 49 states, DC, and 1 territory: 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 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 James 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 5638 US Census records for James Mcmahon, from 1900 to 1950, across 49 states, DC, and 1 territory.
: You'll see James'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 James 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 James 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 James Mcmahon records from the 1900 through 1950 US Federal Census, across 49 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 Mcmahon US Census Records

John Mcmahon Margaret Mcmahon Mary Mcmahon Thomas Mcmahon William Mcmahon

All Mcmahon census records →

Browse More Surnames

Mckenna Mckenzie Mckinney Mclaughlin Mclean Mcleod Mcmanus Mcmillan Mcmullen Mcnally Mcnamara Mcneil

← Back to US Census Records