A toddler was found wandering alone in Battery Park City yesterday — hours after his troubled mother was taken to a hospital, cops said.

It took nine hours before police realized Trevon Frazier, 3, was on his own, officials said.

The tot was discovered at 9:30 a.m. inside Teardrop Park, a 2-acre green space between Warren and Murray streets by North End Avenue, officials said.

Frazier’s emotionally disturbed mom had been taken to Bellevue Hospital hours before her son was discovered, a police source said.

It was unclear whether the boy wandered off from her or was abandoned.

Police and the Battery Park City Parks Conservancy had distributed photos of the boy throughout the area to identify him.

Police calmed the whimpering youngster with a New York Giants blanket.

Officials are vetting Frazier’s relatives in New Jersey before placing him in their care.