Step 1: Recall tribal distribution. The Gaddis are a tribal community found primarily in the state of Himachal Pradesh. Step 2: Area of settlement. They are concentrated in the Bharmour and Chamba districts of Himachal Pradesh. Step 3: Occupation. Traditionally, they are shepherds and pastoralists who rear sheep and goats in the Himalayan region. Step 4: Conclude. Hence, the correct answer is Himachal Pradesh.
\[
\boxed{\text{Himachal Pradesh}}
\]