A woman was found fatally stabbed in the head in Harlem early Tuesday, cops said.

The victim, 39, was discovered unconscious and unresponsive in front of a building on Lenox Avenue near West 130th Street at about 12:15 a.m., authorities said.

Police initially believed she had been shot but investigators soon realized she had been stabbed.

They have not yet identified any suspects and the motive is still unknown, cops said.

The woman is believed to be from The Bronx and she has a prior arrest history, cops said.

Her identity is pending proper family notification.