Ewing-genealogy speaking, the Pittsburgh area was both the target for Ewings emigrating to the frontier in the mid-to-late-1770's and a doorway - a bridge - for many Ewings who used their Pittsburgh area-based relatives as a stepping-stone for migration to Ohio, Kentucky and other farther-west parts of America.

The earliest migrants to the Pittsburgh area, around 1730, were trappers and traders who came to the area when the French claimed sovereignty. There's only annectdotal evidence that Ewings were among them. After the 1763 end of the French and Indian War (the Seven Years' War in Europe), the British controlled the land west of the Allegheny Mountains. Native Americans resisted this change from one foreign nation to another, leading to Pontiac's Rebellion during the first half of 1763.

With the settlement of Pontiac's Rebellion, two things happened. For one, the land in the Pittsburgh area was open for settlement relatively safe from resistance from native Americans. For two, the British decided that settlement was so dangerous that they could not assure safety and declared that settlement was prohibited in the "Indian Land" lying west of the Alleghenies. (It was not until 1769 that this land was officially opened for settlement.)

The Scots-Irish in the Upper Chesapeake Bay area were of a somewhat different mind. They had supported the British in the French and Indian War, they had received little-if-any compensation for this support, they had (in their mind) "won" the western areas, and they felt they had the right to settle these areas. As a result, descendants of John Ewing (1648-1745) of Carnashannagh settled the (then) Redstone, (now) Unionville, area in (now) Fayette County, southeast of Pittsburgh, in the mid-1760s. A bit later, several descendants of James Ewing of Inch descendants of James Ewing of Inch settled the (now) Robinson and Collier Township areas of Allegheny County, Pennsylvania, starting around 1770.

Many cousins, nephews, etc., appear to have followed their relatives to the Pittsburgh area. Some settled and stayed. Some moved on further west, accompanied by cousins who found the opportunities in the Pittsburgh area to be limited and "went west" to find better opportunities. In any event, these "followers" left genealogical records which have survived in the Pittsburgh area's Census Records and its records of Wills, Land Transfers, etc.