Nicholas Disantis, 26, was headed north on the highway at Milepost 104, near Midvale, when his 2009 Chrysler PT Cruiser crossed the center line at about noon Monday and struck a 1996 Jeep Grand Cherokee driven by Krystal Carter, 23, of Emmett.
Disantis, who was not wearing a seatbelt, died at the scene.
Carter and her infant passenger were taken by ambulance to Weiser Memorial Hospital. The Idaho State Police, which investigated the crash, did not have information on their conditions.
The highway was blocked for more than three hours as investigators looked over the scene. The crash remains under investigation.