Answer: Uttarakhand
Notes: Garhwal Himalaya, a sub-range of the Himalayas, is located in the state of Uttarakhand. It is named so because of several Garhs (forts) found in this mountainous region. Recently, a team of researchers found that during 8th Century CE, these forts were strategically built to form clusters and varied levels like valleys, ridges and hill tops. The rulers used them to relay information signals using smoke and fire when facing enemy attack.
