1861年美国的人口总数是多少

约3450万

英文原文
The population of the Northern States was about 22 million while the South had a only about nine million persons. That doesn't say it all, because there were almost 3.5 million slaves included in the South's population count which were a liability. The slave population required guarding and supervision. They were unavailable as troops, because if they were ever given access to arms a slave revolt was certain