Twin Forks was the town on the planet Sphinx.
In 1518 PD, when the Harrington family arrived on Sphinx, it was the closest town to their freehold, but possessed a population of no more than fifty families. At that time, it served as the central hub of all the local freeholds. (SK1)
It was the location of the planetary headquarters of the Sphinx Forestry Service. While visiting it during a state visit to Sphinx, Crown Princess Adrienne was adopted by the treecat Dianchect just before a foiled assassination attempt. (HHA2.2: WPD)