Oldtown is an unincorporated community and census-designated place (CDP) in Allegany County, Maryland, United States, along the North Branch Potomac River. As of the 2010 census it had a population of 86.
It was founded in 18th century colonial times and was initially called "Opessa's Town" or "Shawanese Old Town" because it was the site of a Shawnee Amerindian village abandoned about a decade earlier. In later years the explanatory prefix was dropped from the name and the place because known simply as "Oldtown". Oldtown was begun (on a soon to be busy road) with the building of a trading post along an old Native American trail, the Nemacolin Trail, as traders, especially fur traders (and trappers) pushed through the Cumberland Narrows mountain pass into the Monongahela River valley.
In 1741 Thomas Cresap established a trading post at the abandoned village. A few years earlier, Cresap had figured prominently in the Conejohela War, (also called Cresap's War) concerning the Conejohela Flats area of the Susquehanna River valley, later York County, Pennsylvania. Shortly after his release from prison in Pennsylvania for advocating Maryland's claims, Cresap moved west to the sparsely settled frontier. Lord Baltimore claimed lands at the headwaters of the Potomac River. The move positioned Cresap and his patron to open the as yet uncharted Ohio Country. Cresap and the Delaware chief Nemacolin opened a road westward under the auspices of the Virginia and Maryland speculators of the Ohio Company once they received a charter.