The Agricultural Core
Just outside of Pittsburg lays the Agricultural core of the Untied States. Pittsburg is centered in the overlap between the two regions of the manufacturing and agricultural core. The agricultural core begins in Erie, Pennsylvania and extends up to the Great Lakes and West to the Great Plains. Immigrants from Europe passed through Pittsburg to enter the west where there were more jobs and opportunities. Pittsburg is the gateway between the midwest and Megalopolis.

Source:
http://www.ioling.org/images/maps/iol-2011.png

The Southern Coastlands:On the Subtropical Margin
Oil in Pittsburg
In the river valley of the Allegheny, beneath the surface laid salt and oil wells. Samuel Kier ,a Pittsburg druggiest began selling the oil from the rocks found in the salt wellsin the 1850's. He found that he could use the oil in lamps and thus founded the Pennsylvania Rock Oil Company. Once word got out about his find, investors began taking interest in him and his "black gold". The area transformed from a farm town into a booming oil region. Drill and pumps were made to extract the oil and town were created to support the boom. At the height, Pennsylvania was responsible for 1/3 of the world's oil production. it was not until oil was found in Texas in 1901 that the oil boom ended.




Sources:
http://www.enopetroleum.com/earlyoilpennsylvania.html