Six passengers were on board the Piper fixed-wing aircraft when it crashed shortly after 9 a.m.
Local time into a U.S. Post Office parking lot in Lafayette, Louisiana, police and fire officials told KATC news, a local ABC affiliate.
One passenger on the plane and a person who was either in or near a vehicle on the ground were taken to a local hospital with life-threatening injuries.
Two people in the post office suffered from smoke inhalation and were also being treated at the hospital, Lafayette Fire Chief Robert Benoit said during a brief news conference.
Sports reporter Carley McCord, 30, was among the five passengers who were killed.
McCord, who worked for WDSU News in New Orleans, was the daughter-in-law of Louisiana State University offensive coordinator Steve Ensminger, the station reported.
The private plane was en route to the Peach Bowl in Atlanta where the passengers were to watch LSU play the University of Oklahoma in a college football national championship semifinal game, WDSU News reported.