The Ras Koh Hills is a range of granite hills forming part of the Sulaiman Mountain Range in the Chagai District in Pakistan's Balochistan province. The word Ras means gateway and the word Koh means mountain in Balochi. Ras Koh, therefore, means Gateway to the Mountains. Pakistan's first nuclear tests were carried out in the Ras Koh Hills on 28 May 1998.