SOMERSET, county of the United States in Penn sylvania, bounded by Alleghany county in Maryland S., by Fayette county in Pennsylvania SW., West moreland NW., Cambria NE. and Bedford E. Length from south to north 35, mean width 26, and area 910 square miles. Embracing a large part of an exten sive valley between that particular ridge of the Ap palachian system of mountains called the Alleghany, and another lateral ridge, the Laurel hill, the surface of Somerset county of Pennsylvania is a true moun tain table land, elevated at a mean of at least 1500 feet above the tides of the Atlantic coast, and upwards of six hundred and sixty feet above the level of the Monongahela at Brownsville. This relative height gives to Somerset a climate near, if not altogether, four degrees of Fahrenheit more severe than that of similarlatitude on the eastern coast of New Jersey. The 40th degree of North Lat. and two degrees of Long. W. from Washington City, intersect near the centre of Somerset. The middle parts of New Jer sey, will therefore contrast with the southern moun tain valleys of Pennsylvania. The comparative tro pical climate of the former is usually ascribed to proximity and absence of an open ocean, a cause per haps of a share of the effect, but difference of level is the far more efficient agent.
A very small angle of the south-east part of Somer set is drained by Wills creek branch of Potomac; Youghioghany river, rising in Virginia and Maryland, flows north into Pennsylvania, forming for 8 or 9 miles part of the boundary between Fayette and Somerset counties, receiving from the latter a large confluent, Castleman's river. The northern section towards Cambria is drained by the south-eastern sources of Conemaugh river. Though bounded by two moun tain ridges, Somerset is rather level than even hilly. The soil is various, and generally well adapted to grain and meadow grasses.
The intended Chesapeake and Ohio canal is pro jected to pass over the southern part of Somerset by the valley of Castleman's rive”.
Somerset, the scat of justice, is situated near the centre of the county, N. Lat. 40°. Long. W. from Washington City 2° 05' Population of the county, 1820, 13,374, or 15 to the square mile nearly.