A 17-year-old girl was killed and two 15-year-old girls were seriously injured in a crash overnight in Sumter County. 

The crash occurred at about 1:22 a.m. at CR 221 and CR 232. 

Troopers said a Hyundai Sonata traveling southbound on CR 221 traveled off the roadway for an unknown reason, and collided with a tree. 

The 17-year-old driver was killed and two of her passengers were seriously injured. A fourth passenger, a 1-year-old boy, received minor injuries. 

The crash remains under investigation.