Fallstead can only be found in Toobworld, and only in the anthology episode "Miller's Millions"*.
I've Googled the name and all that comes up are references to people with the last name of Fallstead. As a location it doesn't exist in the real world.
The state is never mentioned, so where might Fallstead be found on the map of TV America?
I'm leaning toward the Western Massachusetts area, free of that "pahk yer cah in Hahvahd Yahd" accent from the Bahstin area. "Fallstead, Massachusetts" just looks and sounds right.
But upstate New York and Connecticut would have worked as well. Pretty much any state in New England... just so long as the rail system led to the state penitentiary. (There's a reason why Henry Miller [Thomas Mitchell] has an overcoat draped over his left arm and why he's standing next to that rather stern-looking fellow.....)
* The episode aired on May 18, 1957 as that week's offering of 'The O. Henry Playhouse'. A few days later, May 22, it was shown again on 'The Ford Television Theatre'. I mentioned all of that in the previous post - as such it seemed appropriate "Miller's Millions" should get the "Two for Tuesday" treatment.....