First of all how many were there during slavery, just before the civil war, also what states had the most free black men?
The free black population in the USA in the 1860 census was 476,748.
http://www.freeaainnc.com/censusstats1790-1860.pdf
(This was the total population of free blacks in the USA, not “free black men”. That is, it includes women and children.)
This compares to the slave population in the same census of 3,950,528.
The total population of the USA in the 1860 census was 31,183,582
http://www.civil-war.net/pages/1860_census.html
225,926 free blacks were in the free states. 250,757 free blacks were in the slave states.
The states with the largest numbers of free blacks in 1860 were:
Maryland – 75,000
Virginia – 58,000
Pennsylvania – 57,000
New York – 49,000
Ohio – 37,000
North Carolina – 30,000
New Jersey – 25,000
Delaware – 20,000
Louisiana – 19,000
Indiana – 11,000