A US congresswoman and three others have been killed in a car crash in the state of Indiana.

Republican Jackie Walorski died in what police say was a head-on collision in Elkhart County at around 12.30pm on Wednesday.

Ms Walorski, 58, had represented Indiana’s 2nd congressional district since 2012.

Police say a northbound passenger car travelled left of the centre line and collided head-on with a southbound SUV.

The Elkhart County Coroner’s Office and the Elkhart County Sheriff’s Office are conducting the investigation.