Before the Civil War? Legally no. In reality? A bit more complicated. If you were legally a slave in the South, you were still a slave in the North.
An educated slave named Dred Scott was taken into a slave free state by his master. Thus, any slave fugitive act (I.E. the slave ran away) didn't apply. Dred Scott sued his master, arguing that since he was taken to the North he is a free man. The case went up all the way to the Supreme Court.
The question is simply this: can a negro whose ancestors were imported into this country and sold as slaves become a member of the political community formed and brought into existence by the Constitution of the United States, and as such become entitled to all the rights, and privileges, and immunities, guarantied by that instrument to the citizen, one of which rights is the privilege of suing in a court of the United States in the cases specified in the Constitution?
Basically, the court asked "can slaves/children of slaves be citizens? They eventually answered that question as thus:
... We think they are not, and that they are not included, and were not intended to be included, under the word "citizens" in the Constitution, and can therefore claim none of the rights and privileges which that instrument provides for and secures to citizens of the United States. On the contrary, they were at that time considered as a subordinate and inferior class of beings who had been subjugated by the dominant race, and, whether emancipated or not, yet remained subject to their authority, and had no rights or privileges but such as those who held the power and the Government might choose to grant them.
So, the Supreme Court of the United States, in a 7-2 ruling, declared that while a black person could be granted citizenship of a state, they could not become "real" citizens of the Union, nor does a slave become free by going to a slave free state.
However, both people and states didn't enforce Dredd Scott or fugitive slave laws. As soon as a slave escaped North, 90% of the time the only way their Southern master could only drag their slave back south was to send a bounty hunter to find the escaped slave. The lack of enforcement of the Fugitive Slave Act was even mentioned in Declaration of Imediate Causes by South Carolina.
Incidentally, sometimes these bounty hunters were not particularly picky about which black person they brought back South as the "escapee". Twelve Years a Slave was a memoir of a free black man who was kidnapped by bounty hunters and lived his life as a slave for twelve years.
Plenty of slaves didn't just stop in the North, they fled all the way up to Canada to be out of the reach of anyone who wanted to drag them back to the cotton plantations.
So, to answer your question: Legally a slave in the North wasn't free. Pratically they were probably free, but still at risk of being taken back.
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Hi there, would you be able to clarify your question please? It's not quite clear what you're asking.