IC 2177 is a region of nebulosity that lies along the border between the constellations Monoceros and Canis Major. It is a roughly circular H II region centered on the Be star HD 53367. This nebula was discovered by Welsh amateur astronomer Isaac Roberts and was described by him as “pretty bright, extremely large, irregularly round, very diffuse.”

The name Seagull Nebula is sometimes applied by amateur astronomers to this emission region, although it more properly includes the neighboring regions of star clusters, dust clouds and reflection nebulae. This latter region includes the open clusters NGC 2335 and NGC 2343.