An off-duty NYPD cop was killed in a single-car crash on Long Island late Monday night, according to police.

Ryan McKenna, 30, was driving a 2018 Nissan Frontier east on the Long Island Expressway, just west of exit 53, when the vehicle struck the median and overturned around 10:55 p.m., Suffolk County police said.

McKenna, of Hicksville, was taken to South Shore University Hospital in Bay Shore where he died, cops said.

The vehicle was impounded for a safety check. 

McKenna worked for the NYPD for 4 1/2 years and was assigned to Police Service Area 9 in Queens, police said.