Robert of Clermont could look out from his front door, cast his gaze upon the Catskill Mountains, and declare that he owned all he could see. But could he do that honestly? Yes and no. He owned perhaps a third of the Great Hardenbergh Patent, which encompassed the Catskill Mountains. But which third? And how many acres did that actually amount to?
Since the Patent spent almost half a century without being properly surveyed, its boundaries remained loosely defined. Eventually, as the land around it was claimed, it began to be roughly defined by its shared borders with other patents. Of course, in land disputes, roughly defined borders wind up in court. It seems that a number of lawyers made quite a bit of money off the Patent, as owners of the surrounding land did battle over who owned what.
But the Indians themselves didn't practice land ownership, and control over a given piece of land could be very fluid. The question arose of which group of natives one needed to approach. Of course, unscrupulous colonists could take advantage of this confusion. It seems that there were certain Indians who were willing to say with a straight face that they controlled any given piece of land, and were willing to sign it over for a very reasonable price.
It's not immediately clear who Johannes Hardenbergh approached. Most likely it was some portion of the River Indians – a loose category that included the Esopus and Mahican Indians. But whatever claim this group might have had was disputed by the Mohawk, at least over the western portion of the Catskills. The Mohawk went so far as to threaten war on the various members of the River Tribes if the Hardenbergh Patent included the northwest Catskills and the lands around the Delaware river.
Those were just the official problems, and there were innumerable smaller problems. Many of the early New Yorkers had a practical approach to land ownership: if it wasn't currently occupied, then it was free for the taking. The responsibility for dealing with such attitudes fell to Johannes Hardenbergh himself. From the time the Patent was granted until shortly before he died, Johannes rode the trails of the Catskills, forcing out squatters, fending off lumber thefts and correcting the occasional straying fenceline.
Between policing his land, bargaining with the Indians and making the occasional court appearance, Johannes was never able to get the land surveyed, which just extended the problem. Not only was the lack of external boundaries a problem, but the lack of internal partitions meant that the owners could never divide up the land and lay claim to their share. Johannes died in 1745, while the Patent bearing his name was still six years from being properly surveyed. In his will, he directed that his sons should sell off his shares and give up on the Patent.
The lack of internal partitions meant that Robert of Clermont could not be absolutely sure which third of the Patent was his. The lack of external boundaries meant that he could never be sure how many acres his third share made up. Estimates of the total acreage for the Patent range from 1 million acres to two million acres, which is quite a range. The 1.5 million acres is a guess in hindsight, based on modern maps and boundaries set by decades of legal wrangling.With the death of Johannes Hardenbergh, de facto control over the fate of his Patent passed on to the largest single landowner, which happened to be Robert. Under Robert, lagging surveys that were set into motion under Johannes were finally completed and the Patent was finally defined, divided and distributed. At some point in the 1750s, Livingston was able to claim some of the northeastern portion of the Catskills and lands south to what is now Woodstock. More than a decade after buying in, he was able to truly say that he owned all he could see, without squinting.