John Herschel discovered NGC 3817 = h947 on 18 Jan 1828 and noted "F. The first of 4 [with NGC 3819, 3822 and 3825]." His position is at the south edge of NGC 3817.

400/500mm - 17.5" (4/25/87): fairly faint, fairly small, oval ~E-W, brighter core. A mag 11 star is 2.7' NNW of center. First of five in the field in HCG 58 with NGC 3819 4.3' NE, NGC 3822 4.7' ESE, NGC 3825 7.9' ESE and NGC 3820 5.7' NNE. This group is superimposed on distant galaxy cluster Abell 1356.

Notes by Steve Gottlieb