Bergen County developed as the largest slaveholding county in the state,[1] in part because many slaves were used as laborers in its ports and cities. After the Revolutionary War, many northern states rapidly passed laws to abolish slavery, but New Jersey did not pass abolish it until 1804, and then in a process of gradual emancipation similar to that of New York. But, in New Jersey, some slaves were held as late as 1865. (In New York, they were all freed by 1827.) The law made African Americans free at birth, but it required children (born to slave mothers), to serve lengthy apprenticeships as a type of indentured servant until early adulthood for the masters of their slave mothers. New Jersey was the last of the Northern states to abolish slavery completely. The last 16 slaves in New Jersey were freed in 1865 by the Thirteenth Amendment.[2]
My understanding is that slavery was outlawed in NJ in 1846; Bergen County was also home to “Skunk Hollow”, a settlement of free blacks from the early 1800s (at a time when most weren’t free).