The domain of ancient Pemaquid is the region between the Penobscot River and the Kennebec River. Below is a modern day road map of the general area showing north as far as Bangor.
Below is a close-up showing the ancient Pemaquid area. Please pardon our editing to remove some of the less relevant stuff. We have also added markers for the rivers as these are hard to read on the map.
For comparison, here is plate 6 and an enlargement from Morris, Gerald E., Ed. (1976). Maine bicentennial atlas: An historical survey. The Maine Historical Society, Portland, ME.
Enlargement of upper right corner, here you can clearly see that Champlain
has labeled Norumbegue on the Penobscot River.
The above two illustrations were scanned from Phillip Viereck's 1967, The new land: Discovery, exploration, and early settlement of northeastern United States, from earliest voyages to 621, told in the words of the explorers themselves. John Day Co., New York, NY. Used with permission of Phillip Viereck.