We present the validation and characterization of Kepler-61b : a 2.15 R _ { \oplus } planet orbiting near the inner edge of the habitable zone of a low-mass star . Our characterization of the host star Kepler-61 is based upon a comparison with the set of spectroscopically similar stars with directly-measured radii and temperatures . We apply a stellar prior drawn from the weighted mean of these properties , in tandem with the Kepler photometry , to infer a planetary radius for Kepler-61b of 2.15 \pm 0.13 R _ { \oplus } and an equilibrium temperature of 273 \pm 13 K ( given its period of 59.87756 \pm 0.00020 days and assuming a planetary albedo of 0.3 ) . The technique of leveraging the physical properties of nearby “ proxy ” stars allows for an independent check on stellar characterization via the traditional measurements with stellar spectra and evolutionary models . In this case , such a check had implications for the putative habitability of Kepler-61b : the planet is 10 % warmer and larger than inferred from K –band spectral characterization . From the Kepler photometry , we estimate a stellar rotation period of 36 days , which implies a stellar age of > 1 Gyr . We summarize the evidence for the planetary nature of the Kepler-61 transit signal , which we conclude is 30,000 times more likely to be due to a planet than a blend scenario . Finally , we discuss possible compositions for Kepler-61b with a comparison to theoretical models as well as to known exoplanets with similar radii and dynamically measured masses .