In 1870 about twenty-five independent refineries, many of them prosperous and powerful, were manufacturing oil in the city of Cleveland; two years afterward this new Standard Oil Company had absorbed all of them except five: In these two critical years the oil business of the largest refining center in the United States had thus passed into Rockefeller's hands.

By 1874 the greatest refineries in New York and Philadelphia had likewise merged their identity with his own.
When Rockefeller began his acquisition, there were thirty independent refineries operating in Pittsburgh, all of which, in four or five years, passed one by one under his control.

The largest refineries of Baltimore surrendered in 1875.
These capitulations left only one important refining headquarters in the United States which the Standard had not absorbed.

This was that section of western Pennsylvania where the oil business had had its origin.

The mere fact that this area was the headquarters of the oil supply gave it great advantages as a place for manufacturing the finished product.
The oil regions regarded these advantages as giving them the right to dominate the growing industry, and they had frequently proclaimed the doctrine that the business belonged to them.