I live a few miles from the site of Cresap's Fort (1730's) a few miles south of modern Wrightsville PA. Unfortunately, the site was flooded for a hydro-electric dam during the 20th century. There were a number of small towns and a canal along the river, most of which is now submerged. Cresap's Fort was built by a MArylander, trying to protect Maryland's claim to the land south of Wrightsville on the West side of the Suquehanna. Cresap himself evicted many Pennsylvania settlers from their lands. I know a string of frontier forts was built along the frontier in the 1750's to protect from the French and Indians. But it seems if Cresap built a fort along the river, that other's must have built forts as well. (Sometimes fort is a generous term for what existed) Does anyone have any references to other forts along the lower Susquehanna before the 1750's?
a quick google search turned up lots of articles (799,000) of which I looked at this one and found it interesting: http://usgwarchives.net/pa/1pa/1picts/frontierforts/frontierforts.htm