The Hag was a rock formation on the side of Hellbent Mountain within the White Mountains of New Hampshire. Viewers standing below Hellbent Mountain looking above the correct angle would see the face of an old witch: "people came from all over the country to gape at the Hag and take pictures of it and buy souvenirs in the various gift shops in the area" (The Curse of the Blue Figurine, 147).
A number of touristy trinkets and stops in the area are named for the formation, such as Hag Kumfy Kabins, Hag Lake, Hag View Cottages, Haggis Baggis Bar and Grill, and Hagtooth Harry's Bear Ranch. When the great stone face collapses into the Hag Lake – supposedly related to the remains of Father Baart – Professor Childermass considers the number of things that will have to change their name, much to his amusement (Curse, 180-1).
The Hag is Bellairs’s take of one of New Hampshire’s prized symbols, the 40-foot-tall Old Man of the Mountain, or the Great Stone Face, immortalized by American authors Nathaniel Hawthorne and Daniel Webster, the latter of which famously noted:
"Men hang out their signs indicative of their respective trades; shoe makers hang out a gigantic shoe; jewelers a monster watch, and the dentist hangs out a gold tooth; but up in the Mountains of New Hampshire, God Almighty has hung out a sign to show that there He makes men."
The Old Man was a natural stone formation on the side of Cannon Mountain that was first reported in 1805. Looming 1,200 feet above Profile Lake, centuries of weathering took its tole on the rocks - many of which were eventually held in place with steel cables and turnbuckles - until May 3, 2003, when the Old Man fell into the waters below. Overnight, the official New Hampshire state emblem was gone.
Hag also seems to be a favorite word of Bellairs as it appears elsewhere in his writing.