My house was built on a Penn's land grant, as were those of most of my family, early 1700's. The very oldest among them were just squatters, they built wherever the hell they wanted in the 1690's, and only came into legal ownership of the land they'd been living and farming on 30-40 years later. Another house, which my great-grandparents later owned, was somehow built the land Wm. Penn had intended to set aside for his own house. Surprisingly, he was gracious enough to move to another location 15 miles away, when he built his home here in SE PA.
I believe that his son(s) actually handed out or sold more land grants than Wm. Penn himself, and one interesting thing about these grants is that they were often done on condition that the recipient build on and live on the land. In the case of my house, the grant given in the 1730's was later revoked for not satisfying all of the conditions, given to another neighbor and then eventually sold to the man who built the largest part of the house in 1775. You can see an earlier and smaller stone structure that presently makes up one corner of our present walk-out basement, which was seems to have been the main living level of this earlier 1730's owner's house.