Resuming the day on 282/2, Himachal lost Ankush Bains on his overnight score of 156 but Dogra, batting on 76, went on to notch up a huge score with the help of 20 boundaries and three sixes at the Barsapara Cricket Stadium.
In reply, Assam were 18 for no loss at stumps on the second day.
Assam trailed by 531 runs with 10 wickets remaining in the first innings.