The inhabitants of Upper Merion derived quite a bit of wealth from its mines and quarries. The three large furnaces for the manufacture of iron were located at Port Kennedy and two others were on the Schuylkill below Swedesburg. The ore was obtained in the vicinity of Valley Forge, Gulf Mills, and King of Prussia, and it was estimated that one fifth of the area of the township abounded in this mineral. For the year ending June 1, 1857, Port Kennedy exported lime to the value of $140,000. In 1840, the whole county produced lime to the amount of $236,162. This sum was surpassed in value by Upper Merion alone. (Courtesy of the King of Prussia Historical Society)
Fact published 6/3/16 Upper Merion Township E-Newsletter