Fanning's Illustrated Gazetteer of the United States... (New York: Phelps, Fanning & Co., 1853), 22.
ALLEGHANY COUNTY, in the extreme western part of Maryland, bordering on the north side of Potomac river. Entire length 65 miles; bready very unequal, averaging about 124, with an area of about 800 square miles. This county is traversed by the main chain of the Alleghany mountains, which discharge the upper branches of the Youghiogheny into the Potomac. The face of the country is excessivley broken and rocky, notwithstanding there is muh excellent arable land in the valleys, and some even on the mountain plains. the mountains contain extensive beds of bituminous coal, that of Frostburgh being of superior quality. Courts are held at Cumberland. Pop. in 1820, 8,654; in 1830, 10,609; in 1840, 15,686; in 1850, 22,769.