William Herschel discovered NGC 3815 = H III-339 = h946 on 10 Apr 1785 (sweep 394) and recorded "vF, vS, goes into the field with the foregoing [NGC 3812]. He discovered[NGC 3812 4 nights earlier, but missed NGC 3815. JH called this galaxy "Not vF; pL; 30"." and measured an accurate position.

400/500mm - 17.5" (4/15/93): fairly faint, fairly small, elongated 2:1 WSW-ENE, broad concentration. Last in a small group (LGG 245) with NGC 3814 2.5' W, NGC 3812 6.7' WNW and NGC 3798 20' WSW. Located 5.8' ESE of mag 8.4 SAO 81942.

Notes by Steve Gottlieb