  In this Letter, we announce the discovery of a new dwarf satellite of the
Milky Way, located in the constellation Canes Venatici. It was found as a
stellar overdensity in the North Galactic Cap using Sloan Digital Sky Survey
Data Release 5 (SDSS DR5). The satellite's color-magnitude diagram shows a
well-defined red giant branch, as well as a horizontal branch. As judged from
the tip of the red giant branch, it lies at a distance of ~220 kpc. Based on
the SDSS data, we estimate an absolute magnitude of Mv ~ -7.9, a central
surface brightness of mu_0,V ~ 28 mag arcsecond^-2, and a half-light radius of
\~ 8.5' (~ 550 pc at the measured distance). The outer regions of Canes
Venatici appear extended and distorted. The discovery of such a faint galaxy in
proximity to the Milky Way strongly suggests that more such objects remain to
be found.
