Five other people were injured in the crash that occurred at 11:50 a.m. at Route 110 and Harrison Avenue, near the hamlet's fire company, police said.
The fatally injured victim, Cathy Rich, 55, was seated in the backseat of a 2005 Toyota RAV4 driven by her niece, Briyonna York, 18. After traveling south on 110, York was making a left turn onto Harrison when her vehicle was struck by a 2008 Toyota Tacoma headed north, police said.
Rich was pronounced dead at Good Samaritan Hospital Medical Center in West Islip -- the same facility where the RAV4's front-seat passenger, York's mother, Stacy Johnson, 37, was treated for nonlife-threatening injuries.
A third passenger, Dana Gilley, 35, was airlifted to Stony Brook University Hospital, where he was listed in stable condition, police said. All four of the RAV4's occupants lived together, police said.
The driver of the Tacoma pickup, Jose Sanchez-Jurado, 23, of Fredericksburg, Va., was also taken to Good Samaritan to be treated for nonlife-threatening injuries.
Shortly after the wreck, officers said there didn't appear to be any criminality involved on the part of either driver. Police, however, impounded both vehicles for safety checks and will continue investigating. Anyone with information may call Suffolk police First Squad detectives at 631-854-8152.
With Jennifer Barrios