Brunswick is located in southwestern Frederick County on the banks of the Potomac River. It was established on the now-defunct Chesapeake and Ohio Canal, but really expanded in the late 1800s when the Baltimore and Ohio Railroad built their six-mile-long rail yard nearby. In 1890 the city was incorporated as Brunswick and became an official 'railroad town'. (It was previously known as Berlin and has been known over the years as Buffalo Wallow, Coxson Rest, Eels Pot, Potomac Crossing, Tankersville, and Barry.) Brunswick is now a major stop on the MARC commuter train line out of Washington, DC. As of the 2010 census it had a population of 5,900.