Brunswick is located at 43°54'51" North, 69°57'56" West (43.914167, -69.965833).
According to the United States Census Bureau, the town has a total area of 14.04 mi2 (36.36 km2). 12.58 mi2 (32.58 km2) of it is land and 1.46 mi2 (3.78 km2) of it is covered by water. The total area is 10.39% water.
Brunswick is located in the Eastern Standard Time (EST) timezone, GMT-05:00. It observes Daylight Saving Time (DST).