By 1804, all of the Northern states had abolished slavery or set measures in place to gradually abolish it, although there were still hundreds of ex-slaves working without pay as indentured servants in Northern states as late as 1840.
By 1804 (including New York (1799) and New Jersey (1804)), all of the Northern states had abolished slavery or set measures in place to gradually abolish it, although there were still hundreds of ex-slaves working without pay as indentured servants in Northern states as late as the 1840 census . Found on the internet.