Rockville and the Town of Vernon were consolidated in 1965.
In 1935 Rockville City was the county seat of Tolland County and a thriving textile city, producing fine wool fabrics and silk fishlines. The U.S. Envelope Company operated a mill here, dating from 1856, where Milton G. Puffer is reported to have perfected a machine that counted, as well as folded, envelopes. In 1802 one of the country's earliest wool carding mills opened here. The original owners of the Rock Mills would not employ a man unless he was a Congregationalist; in each workman's bobbin box was placed a Bible to be read during dull moments.