When the Pennsylvania Railroad was planning the extension of its line through Charles County in 1869, it established a stop in the middle of an oak forest to serve several prosperous farms. The eastern side of the right-of-way in that area had been donated by the Chapman family from its property called La Plata Farm; the western side was sliced from the Stonestreet family farm. On its route map, the railroad chose to label the stop “La Plata Station.” The station built there in 1888 is still in existence.

The community that developed on Chapman-donated land on the east side of the railroad tracks naturally became known as La Plata. A post office was established there in 1873—the same year that the railroad began its service to the town.

As La Plata grew and prospered, a political battle developed at Port Tobacco, county seat of Charles County. Should the county seat be moved to La Plata, 3 miles inland to the east and boasting a railroad siding, telegraph station, and buoyant economy? A special election in May of 1892 maintained the status quo. Port Tobacco won easily.

Three months later, the courthouse at Port Tobacco burned to the ground—but, strangely enough, the records had been carefully removed beforehand. Apparently an incendiary act had been perpetrated. But no one was prosecuted, and no one ever admitted to knowledge of the deed. Feelings ran so high that it was impractical to consider rebuilding the courthouse at Port Tobacco. The situation dragged on until another special election was held in 1895 to determine whether to move the county seat to either La Plata or Chapel Point. This time, La Plata prevailed, mainly because of its location on the railroad.

Without delay, a new courthouse was built of red brick in an imposing Victorian style. It still stands today, with several additions and embellishments. Next to the courthouse, on Charles Street, stands another structure of historical significance—Christ Church of Port Tobacco Parish. That parish is one of the 30 original Church of England parishes created in the Province of Maryland by an act of the Assembly in 1692.