Officials said that at around 6:45 p.m. Friday Chelsea Sorensen, 22 of Nampa, was driving west on I-84 when she lost control of her vehicle, drove into the median and flipped her car over.
The car went into the eastbound lanes and hit a Nissan Maxima carrying the Bowen family from Burley.
Sorensen was flown to St. Alphonsus Regional Medical Center in Boise, where she died from her injuries.
The driver of the Nissan, 23-year-old Ryan Bowen, died at the scene.
Franklin Bowen, 52, Nedra Bowen, 50, and Loralee Bowen, 17, were also flown to St. Alphonsus to be treated for their injuries.
Hospital officials told KBOI2 News that the other Bowen family members are in stable condition.
Police said that everyone in the crash was wearing a seat belt.
Both of the eastbound I-84 lanes were blocked for around 4 and a half hours while crews worked the scene. Police are still investigating the crash.