Was Mt. Tom Reservation in Holyoke, MA ever an active volcano?

Answer 1

Sort of, but not really.

Mt. Tom is part of a traprock ridge system. Traprock ridges are formed from old basalt flows. These flows accumulate in layers, then much later are tilted up into angled ridges.

Follow that with millions of years of erosion and soil deposition, and colonization by plants and animals, and you get Mt. Tom.

So no, the mountain was never a volcano - but it was created by one (or several).