Magill Bay is on the Pontook Reservoir, which was created by a hydroelectric dam. The reservoir is popular for fishing, boating, and birdwatching. 

Magill Bay is adjacent to Berlin Road (NH-16).

The Androscoggin River is a river in Maine and New Hampshire. It is 178 miles long and joins the Kennebec River at Merrymeeting Bay in Maine before its water empties into the Gulf of Maine on the Atlantic Ocean. The river originates from Umbabog Lake in Coos County, New Hampshire, and flows through scenic landscapes, historic towns, and industrial areas.

The name "Androscoggin" comes from the Eastern Abenaki term meaning "river of cliff rock shelters" (literally "thus-deep-dwelling-river"); or perhaps from Penobscot meaning "river of rock shelters".