[Vlad The Inhaler]

By 1860 there were 18 Northern slaves and 4 million Southern slaves.

Not according to the 1860 Census.

http://www.civil-war.net/pages/1860_census.html

1860 Slave Count For Non-Confederacy States

DELAWARE - 1,798
KENTUCKY - 225,483
MARYLAND - 87,189
MISSOURI - 114,931
NEBRASKA - 15

[BroJoeK]

Vlad The Inhaler on Union slaves: "DELAWARE - 1,798 KENTUCKY - 225,483 MARYLAND - 87,189 MISSOURI - 114,931 NEBRASKA - 15 "

First we should note Confederates claimed Kentucky & Missouri and sent armies of conquest to hold them.
They also invaded Maryland, hoping to flip it from Union to Confederate.

Second, those were all Southern slave states except Nebraska, which was a territory, not a state.

Northern free-States had all gradually abolished slavery by 1860 and only a handful remained in one Northern state, New Jersey.
In the mean time Northern freed-blacks increased to over 200,000 by 1860.

[BroJoeK]

Vlad The Inhaler on Union slaves: "DELAWARE - 1,798 KENTUCKY - 225,483 MARYLAND - 87,189 MISSOURI - 114,931 NEBRASKA - 15 "

First we should note Confederates claimed Kentucky & Missouri and sent armies of conquest to hold them.
They also invaded Maryland, hoping to flip it from Union to Confederate.

Second, those were all Southern slave states except Nebraska, which was a territory, not a state.

Northern free-States had all gradually abolished slavery by 1860 and only a handful remained in one Northern state, New Jersey.
In the mean time Northern freed-blacks increased to over 200,000 by 1860.