Port Tobacco is an unincorporated community in Charles County, Maryland, United States.
Once a bustling port providing indirect access to the Potomac River, Port Tobacco was a commercial hub for colonial Maryland and served as the county seat of Charles County from 1658 to 1895. Unfortunately, erosion from excessive agricultural use and poor soil conservation caused significant siltation at the head of the Port Tobacco River, which eventually became unnavigable to larger merchant vessels. As a result, commercial activity at the port had dwindled by the time of the Civil War. In 1888, a small portion of the town's square incorporated as Port Tobacco Village and may have signaled an attempt by the town's residents to address the port's decline. That decline, however, was only exacerbated by the completion of a nearby rail line to Pope's Creek in 1873 operated by the Baltimore and Potomac Railroad. The new line bypassed Port Tobacco and ran further south to another port directly on the Potomac River. New communities eventually sprang up along the railway and prospered, including the town ofLa Plata, which succeeded Port Tobacco as the county seat in 1895. Historic landmarks within Port Tobacco include Chapel Point, home of St. Thomas Manor and St. Ignatius Church, the oldest continuously active Jesuit complex in the world, and the oldest Catholic parish in theThirteen Colonies; Mulberry Grove, the birthplace of John Hanson; and Rose Hill manor house.