Here is a list of what I think are the most prominent mountains in Maine.
I was surprised at their number compared to adjacent states and some non-adjacent states. Each one is an interesting hike and provides a superb view. In fact Maine has something in common with Nevada. Among the states in the lower 48, Nevada has the greatest number of summits exceeding 2000 feet of prominence. Maine is the eastern state having the greatest number of peaks exceeding this as well. The number of peaks in Maine exceeding prominence of 2000 feet is more than all other states aside from the Rocky Mtn, Basin and West Coast states also more than the number in both Texas and South Dakota. While having fewer 2000 foot prominence peaks than Wyoming and New Mexico, the number of such mountains per square mile is greater in Maine.
The prominence of Peak X is defined in terms of the set,A, of contours which contain X and no higher peak.Prominence(X) = Height X - infA
To give a simple example the Prominence of Mauna Kea = its height of 13,796- the height of the beach = 13,796 ft.
The prominence of neighboring Mauna Loa is much less because of the Huumula Saddle between them at 6600 ft. Mauana Loa's height 13,679-6600 = 7079 feet is its prominence
The images below are Katahdin from Turner, White Cap (Piscataquis Co) from the east, Traveler from Lower South Branch Pond by me.
SPers contributions injektilo: Bigelow in Winter,Sugarloaf summer, Winter scene of Old Speck/ Baldpate and a winter scene from the top of Saddleback
Chilkoot: Big Snow Mountain
Rasgoat: Baker Mountain from Little Lyford Pond