George Johnstone Stoney, Lord Rosse's assistant, discovered NGC 3181 on 25 Jan 1851 in an observation of NGC 3184. R.J. Mitchell sketched the the spiral structure on 1 Feb 1856 (fig 13, Plate XXVII in the 1861 publication) and highlighted two brighter knots or sections of the western spiral arm. The elongated knot embedded in the spiral arm on the southwest side is NGC 3181. This HII region is catalogued as [H69] 41 in Hodge's "HII Regions in 20 Nearby Galaxies".

900/1200mm - 48" (4/4/11): NGC 3181 is a bright, 15" knot in one of the spiral arms of NGC 3184. It resides 1.2' SW of the nucleus in a long sweeping arm that wraps around around south side of the core and then heads north on the west side of the galaxy. This is the brightest of a couple of knots resolved in the arms.

Notes by Steve Gottlieb