The Pennsylvania anthracite fields, the principal source of anthracite in North America, are in the eastern part of the Commonwealth of Pennsylvania. The coal occurs in four elongate areas - Northern, Western Middle, Eastern Middle, and Southern fields - that trend northeastward and lie in echelon arrangement. The fields range in length from 24 to 66 miles and in width from a fraction of a mile to 10 miles, and include about 484 square miles of coal-bearing land. The area covered by this report is in the Western Middle field.