The accident happened on Highway 59 just east of Oregon around 3:00 p.m.
Troopers say 48-year-old Jana Parsons, of Forest City, crossed the center line and hit another vehicle head-on.
The crash killed Parsons and the driver of the other vehicle, 61-year-old Michael Ginn of Independence.
A passenger in Ginn's car, 67-year-old Joseph Derr, was taken to the hospital with serious injuries.
It's not known what may have caused Parsons to cross over into oncoming traffic.