The pilgrims, all hailing from Bulandshahr in Uttar Pradesh, were crossing the road near Roli Belwala police station when they were hit by the dumper at around 2:30 AM, SSP Arun Mohan Joshi said.
The victims were rushed to district hospital where four were declared brought dead, Joshi said.
One of the two critically injured persons succumbed at a hospital near Dehradun where they were later taken, he said, adding, the dumper truck has been impounded and its driver arrested.