Calvert County documents the fascinating history of this From its early Piscataway heritage to the advanced research laboratories of today, from the tobacco farms to the sandy beaches, Calvert County has had a fascinating and diverse past. Established in 1654, Calvert played a role in both the American Revolution and the Civil War. Hosting decades of vacationing beachgoers, the region has also been called home by the many who, for centuries, have built their lives on the bounty of the Chesapeake Bay.