Harnai is situated at 166 km from Quetta on the Quetta Road. It is surrounded by different mountain ranges. Normally the weather in Harnai remains pleasant except in few months of summer. As covered within mountains, it is the most beautiful city in the Balochistan Province. There are number of fresh water streams in the district, which use to growing fresh vegetables and fruits.
The Wam Tangi River and the Palosin River are the main river in the district.