An unidentified man was stabbed to death in the Bronx and four others were hurt in separate shootings across the city overnight, police said.

In the deadly incident, a man who was stabbed multiple times in the torso walked into BronxCare Health System, the former Bronx Lebanon Hospital, at around 2 a.m. Saturday.

It is unclear if the staff was able to provide any treatment. Cops said the man died a short time later.

Investigators “have no idea where it happened and when it happened,” said an NYPD spokesman, noting the victim arrived at the hospital by private means.

At about 2:20 a.m., a 27-year-old woman was shot once in the right leg outside 2-4 Astoria Boulevard, near the Astoria Houses, cops said. EMS brought the victim to Elmhurst Hospital in stable condition, police said. The suspect — a man dressed in all gray and black sneakers, ran off, authorities said. There were no arrests.

Less than an hour later, at around 3:15 a.m., a 32-year-old woman was shot in the right leg outside 2422 Webster Avenue, between East 187th and East 188th streets in the Belmont neighborhood of the Bronx, police said. EMS took the victim to St. Barnabas Hospital in stable condition, cops said. There were no arrests.

At around 3:50 a.m., a 35-year-old man was shot in the stomach on 1st Avenue and East 1st Street in Manhattan. The victim, who is expected to survive, was taken by EMS to Bellevue Hospital, police said. The gunman was described as a man wearing a basketball jersey with the number 38 on the back, cops said.

Blood was also spilled in Manhattan Friday evening when a 17-year-old girl was grazed in the head by a bullet outside 830 Columbus Avenue at around 10:10 p.m., police said.

It’s not known if the woman was by herself or with a group when she was wounded, authorities said. EMS took the teen to St. Luke’s Roosevelt Hospital in stable condition, authorities said.

Investigators recovered six shell casings at the scene. There were no arrests.