A View From The Top of Kangra Fort/John Hill
Trigarta is an ancient Himalayan kingdom with its capital at Prasthala (modern Jalandhar) and a fort in the Kangra. The Trigarta Kingdom is mentioned in the Mahabharta's Sabha Parv along with other kingdoms. The founder of Trigarta Susarma/Susharman is credited with building the Nagarkot/Kangra fort.

They also finds mention in the works of Panini who described Trigarta as "Ayudhjeevi Sangha" or a martial republic. Probably, they offered mercenary service to other kings and traders and these services provided necessary resources for the development of the Trigarta Kingdom.

The literary sources concerning Trigarta are supplemented by the numismatic evidences. Coins issued as early as the beginning of the Christian era mentions the kingdom of Trigarta.

The region is mentioned as Susarmapura by a variety of Sanksrit, Buddhist, Jain, and Islamic sources. In fact, the first mention of 'Nagarkot'  came from Islamic documents. The region is also mentioned as Kalindarine in the works of the Greek geographer Ptolemy.