Emergency crews responded to the northbound lanes of the highway at about 8:39 p.m.
Police said that both vehicles involved were traveling north on U.S. 31. Jenna Emery, 70, of Grand was in the right lane and Michelle Kunde, 47, of Battle Creek was in the left lane.
The crash occurred when Emery abruptly turned her 1998 Chevrolet Impala left in front of Kunde’s 2008 Ford.
The collision caused Emery’s car to rollover into the median. Kunde’s vehicle ended in the ditch.
Emery was pinned inside her vehicle and was extricated by Port Sheldon Township firefighters. She was transported in serious condition to Holland Hospital by North Ottawa Community Hospital ambulance.
Kunde went by private vehicle to North Ottawa Community Hospital for treatment of minor injuries, according to Ottawa County Sheriff Sgt. Eric Westveer.
The crash remains under investigation.