Maine continues to see a migration of its population away from the most northern areas and toward the south and mid-coast. Within counties such as Oxford and Penobscot, their southern most communities are growing while the smaller northern towns decline in population.
Trends over two decades affirm the north-south divide in terms of population. This has had political effects as the First Congressional District (in the south) has contracted geographically at each recent redistricting to allow the Second Congressional District to expand and include an equal number of residents.
In 2010, the three most densely populated counties (York, Cumberland, and Androscoggin) accounted for over 44 percent of the state’s residents. By contrast, the six least densely populated counties accounted for less than 20 percent.
Source: http://quickfacts.census.gov/qfd/states/23000.html