. along State Route 9 State Route 9 is a meandering highway that works its way from
New Hampshire to
Canada. It frequently runs
concurrently with other highways listed below and also frequently changes direction. State Route 9 runs through most of Maine's major cities including
Biddeford,
Saco,
South Portland,
Portland,
Augusta, and
Bangor. Over the years, a number of improvements have been made by the Route 9 Committee, a partnership of local government officials and business interests in the Baileyville-Calais area.
The Airline The leg from Bangor to
Calais is often referred to as "The Airline," commonly thought to be because of its shorter route than the older
U.S. 1. (Before the coming of
air travel, the term
airline often referred to such a shortcut.) Although anecdotes about unexploded ordnance deriving from bombers flying from the former
Dow Air Force Base (now
Bangor International Airport) using a number of towers and landmarks along "The Airline", in fact the term goes back to the early 1850s as a contrast to the
shoreline route. The last section of "The Airline" was paved in 1973 in Crawford and many old sections of the road are visible to the side of the present roadway. The "Whale's Back", a two-mile stretch built atop an
esker in
Hancock County was one of the most notable features of the highway until it was rebuilt.
Bypass of Brewer Plans to extend
I-395 connecting it to SR 9 began as early as 2001. In February 2008,
MaineDOT suggested five possible routes to extend I-395 to SR 9, with two in particular designated as "State's Choice" and "Holden's Choice". The state approved the "Holden's Choice" route, designated 2B-2. All three affected communities issued resolutions in 2014 opposing this route. The state went forward with the project not as an I-395 extension but as a
super two rerouting of SR 9. The design was finalized in 2021, with construction commencing in 2022. MaineDOT completed the project with a ribbon cutting ceremony on June 27, 2025. When it opened, the existing segment of Route 9 that ran through the downtown areas of
Hampden,
Brewer and Bangor became Route 9 Business. ==Junction list==