Messier 109, also know as NGC 3992, is a barred Galaxy in the constellation of Ursa Major, or better know as the Big Dipper. Located 55 million light years away, with an apparent magnitude of 10.6, it's right below Phecda in the Big Dipper. Because of its location, it's considered one of the easier Messier objects to find. (M109 has also been known to have supernovae pop up in the past).
M109 was first discovered by Pierre Mechain on March 12, 1781, and later confirmed by Charles Messier. Charles cataloged it as NGC 3992 and M99 at the time, but later it was to be cataloged as M109. M109 and any other Messier object above M103 were not considered official objects until Owen Gingerich declared so in 1953.
See a larger image here.