Harry Collins was a citizen of Nipton.
Harry Collins, during Caesar's Legion attack, barricaded himself in his home to protect his "vital essence." He was very paranoid and prepared for such an event. In his house, there are land mines, rigged shotguns, several weapons, and a cage of man-eating bark scorpions. There are two recruit legionary corpses on the floor, indicating that he did not go as easily as Vulpes Inculta suggested.
Harry Collins is mentioned only in Fallout: New Vegas.