Meeting the Cool Neighbors. IV. 2MASS 1835+32, a Newly Discovered M8.5 Dwarf within 6 Parsecs of the Sun

We present observations of 2MASSI J1835379+325954, a previously unrecognized late-type M dwarf within 6 pc of the Sun. Identified based analysis of the Two Micron All Sky Survey optical spectroscopy and photometry indicate a spectral type of M8.5. The star has a proper motion of 0.759" yr^-1 and is clearly visible on both POSS I and POSS II photographic plate material, but it may have escaped detection in previous surveys through its proximity to the Galactic plane. We discuss potential implications for the completeness of the local stellar census.