Maine State Route 15 is a north-south highway in Penobscot County. It runs as a by-pass route in the Bangor Metro Area. This has one business route while in Penobscot County. While in Penobscot County, it runs from the Penobscot/Hancock County Line, near Bucksport, to the Penobscot/Piscataquis, near Dover. ME St Rt 15 passes through the following towns in Penobscot County. Brewer Bangor Corinth Charleston ME St Rt 15 is multi-plexed in Penobscot County. Interstate 395, from Brewer to Bangor.