Police official Kesh Bahadur Shahi said 10 districts have been flooded, with rescuers recovering 54 bodies. The death toll is expected to rise.
It has been raining since Thursday in the region, about 250 miles west of the capital, Kathmandu.
Roads have been either flooded or blocked by landslides in the districts. Power and communication towers were also knocked down, stranding thousands of people in the area.