Dear Marla:
What a great find in the antique shop!

The Mount Pleasant referred to is most likely in Westchester County, near
Tarrytown and Pleasantville. There is both a town (in NYS, a town is a
subdivision of a county) and a hamlet of Mount Pleasant. I believe the
Rockefeller estate of Pocantico Hills is in the town of Mount Pleasant.

Edward Knoblauch