The 1900 US census is a goldmine of information in comparison to censuses conducted in earlier decades. The month and year of birth are given, birthplaces of both parents, and how many years a person has been married. For immigrants to the US the year of immigration is also specified.
| Alabama | Alaska | Arkansas | Arizona |
| California | Connecticut | Colorado | District of Columbia |
| Delaware | Florida | Georgia | Hawaii |
| Iowa | Idaho | Illinois | Indiana |
| Kansas | Kentucky | Louisiana | Massachussetts |
| Maryland | Maine | Michigan | Minnesota |
| Missouri | Mississippi | Montana | North Carolina |
| North Dakota | Nebraska | New Jersey | New Hampshire |
| New Mexico | New York | Nevada | Ohio |
| Oklahoma | Oregon | Pennsylvania | Rhode Island |
| South Carolina | South Dakota | Tennessee | Texas |
| Utah | Virginia | Vermont | Washington |
| Wisconsin | West Virginia | Wyoming | Military and Naval |
| A | County |
| B | Township |
| C | First name |
| D | Last name |
| E | Page # |
| F | Line # |
| G | Dwelling # |
| H | Family # |
| I | Address |
| J | Street |
| K | Relationship to head of household |
| L | Race |
| M | Gender |
| N | Month of birth |
| O | Year of birth |
| P | Age |
| R | Years married |
| S | Number of live births |
| T | Number of children surviving |
| U | Place of birth |
| V | Father's place of birth |
| W | Mother's place of birth |
| X | Year of immigration |
| Y | Years in US |
| Z | "na" indicates naturalized citizen |
| AA | Occupation |
| AB | Months unemployed |
| AC | Months in school |
| AD | Able to read |
| AE | Able to write |
| AF | Able to speak English |
| AG | Rent (r) or own (o)home |
| AH | Home owned free (f) or mortgaged (m) |
| AI | Home (h) or farm (f) |
| AJ | Number of agricultural schedule |