For navigation, the magnetic variation in the area is 15° 3′ W
To find the magnetic variation (declination) in other areas, go to: NOAA Magnetic Variation Calculator
NOAA chart 13296 covers the area roughly north of Five Islands on Gerogetown Island and includes KBC and Beal Island. NOAA chart 13295 covers the area roughly south of Five Islands (and including all of Five Islands) on Gerogetown Island.
You can also purchase a waterproof version of this chart. It is usually available at LL Bean, Kittery Trading Post, Hamilton Marine or West Marine. You can also purchase it online from: Maptech