When researching in the period of the Civil War in the United States, consider what area the contemporary state was:
| Northern States | California | Connecticut | Illinois | Indiana |
| Iowa | Kansas | Main | Massachusetts | |
| Michigan | Minnesota | New Hampshire | New Jersey | |
| New York | Ohio | Oregon | Pennsylvania | |
| Rhode Island | Vermont | West Virginia | Wisconsin | |
| Southern States Seceded before 15 April 1861 | Alabama | Florida | Georgia | Louisiana |
| Mississippi | South Carolina | Texas | ||
| Slaves States Did not secede | Arkansas | North Carolina | Tennessee | Virginia |
| Delaware | District of Columbia | Kentucky | Maryland | |
| Missouri | ||||
| Territories not yet formed | Arizona | Colorado | Idaho | Oklahoma |
| Montana | Nebraska | Nevada | New Mexico | |
| North Dakota | South Dakota | Utah Washington |
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This section is drawn from Genealogy by Berry (including map)
