In 1802, Ohio held a convention to draft a new state constitution, which was subsequently adopted later that year. This constitution formally established Ohio as a free state, reinforcing its commitment to abolition. It also addressed issues of governance and set the framework for the state's legal and political systems. Ohio became the 17th state to join the Union on March 1, 1803.
Maryland abolished slavery in 1864 with the passage of the state constitution.
Missouri abolished slavery in 1865. This is the same year the Tennessee and West Virginia states chose to abolished slavery.
No state abolished slavery during the Revolutionary War. Massachusetts via its Constitution of 1780 did not recognize slavery and thusly "abolished" it, but no state abolished slavery as far as I can see before or "around the time" of the Revolutionary War.
New Mexico abolished slavery in 1821
Massachusetts was the first U.S. state to abolish slavery, in a 1783 judicial interpretation of its 1780 constitution.
Slavery was gradually abolished in the border states during the Civil War. Kentucky abolished slavery in 1865 through a state constitutional amendment, while Maryland and Delaware also abolished slavery through state constitutions in 1864 and 1865, respectively. Missouri did not abolish slavery until January 1865 with a new state constitution.
Mississippi became the last state in the United States to abolish slavery in 1995.
The original U.S. Constitution, before the 13th Amendment, included provisions like the Fugitive Slave Clause, which required the return of runaway slaves to their owners. This clause was later nullified by the 13th Amendment, which abolished slavery.
Texas
Delaware abolished slavery through a gradual process. In 1776, the state passed a law that allowed individuals born into enslavement after that year to be freed at the age of 28. Then, in 1865, after the ratification of the 13th Amendment to the U.S. Constitution, slavery was officially abolished in Delaware.
Because the High Court claimed that slavery could not be abolished in any state, as the Constitution gave it protection.
When speaking about the US Constitution, the term used to change this governing document is called an amendment. Since its original ratifications there have been numerous amendments added to it. Important ones abolished slavery and gave women the right to vote.