The victims, who hailed from Chopal area of Shimla district, were returning after solemnising a marriage at Maipul Temple, the police said.
Three persons died on the spot while another succumbed to his injuries on the way to the hospital. They deceased have been identified as Virender(38), Manoj Kumar(28), Hari Singh (53) and Romesh (55), a police official said.
The injured person, identified as Puneet, has been rushed to IGMC hospital here, the official said.