1860
1860 was the eve of the American Civil War. A list of the hundred largest cities is available from the Census Bureau. This was the eighth United States Census.
| Rank | City | State | Population | Notes |
| 1 | New York | New York | 813,669 | |
| 2 | Philadelphia | Pennsylvania | 565,529 | The large jump in population between the seventh and eighth censuses is due to the 1854 Act of Consolidation, which merged the County and City of Philadelphia into a single government entity and abolished all other local governments. |
| 3 | Brooklyn | New York | 266,661 | |
| 4 | Baltimore | Maryland | 212,418 | |
| 5 | Boston | Massachusetts | 177,840 | |
| 6 | New Orleans | Louisiana | 168,675 | |
| 7 | Cincinnati | Ohio | 161,044 | |
| 8 | St. Louis | Missouri | 160,773 | |
| 9 | Chicago | Illinois | 112,172 | First appearance in the top 10. In the previous census, it was the 24th largest American city with a population of 29,963. Chicago would be one of the world's fastest growing cities in its infancy. |
| 10 | Buffalo | New York | 81,129 | First appearance in the top 10. Would disappear from list by next census and not re-appear until 1900. |
Read more about this topic: Largest Cities In The United States By Population By Decade