The boundaries of Mahendragarh and Rohtak districts were altered so as to make the Rewari district. Rewari and Bawal tahsils (taken from Mahendragarh district) and Kosli except 6 villages of Rohtak district constituted into Rewari district as on November,1,1989.
Kosli was upgraded to the level of sub-division during the same period. By 31-12-1990, the district had two sub-divisions (Rewari and Kosli) and 3 tahsils (Rewari, Bawal and Kosli). Rewari sub-division has been functioning since 1965.Rewari, Khol, Jatusana, Bawal and Nahar were as block headquarters.