Mount Airy is a town located in Carroll and Frederick counties in the U.S. state of Maryland. It is part of both the Washington Metropolitan Area and Baltimore Metropolitan Area. As of the 2010 census the population was 9,288.
The town was originally settled in the early 1830s by a core group of six families. Dorsey, Davis and Bussard were the most prominent names in that first settlement, which was followed closely by the construction of the B & O railroad line in 1831. Because Mount Airy sits at an elevation of 830 feet (250 m), a series of four inclined planes were constructed in order for the trains to climb the steep hills. Locomotives and cars were lifted with the assistance of horses and steam winches. Passengers had to disembark during this process. Plane #4, located west of the town at the intersection of Woodville Road and MD Route 144, is still a recognized location today. In 1839 the planes were abandoned, and the new line was constructed north of where Mount Airy is today. This was a result of more powerful locomotives that had been constructed and heavier loads were being hauled. In 1901, a railroad tunnel was constructed on the south side of town and the existing line into town became a spur line into the center of Mount Airy. The town named the first resident, Henry Bussard, the station agent for the new train station. Mr. Bussard was the first major landowner in Mount Airy.With the incorporation of the town in 1894 came the establishment of the town government structure, including a mayor and council. The first Mount Airy mayor was Byron S. Dorsey, who served ten years in that office between 1894 and 1904.