John Herschel discovered NGC 3260 = h3257, along with NGC 3257 and 3258 on 2 May 1834 (sweep 447) and recorded "eF; vS; R; slbM; 6"." He recorded 4 observations.

Lewis Swift likely found this galaxy on 30 Dec 1897 and reported Sw. XI-108 as "eeeF; eeS; R; eF * in contact; [south-preceding] of 3267." Herbert Howe examined Swift's position in 1900 and found "[NGC] 3257, 3258 and 3260 are in the same field, and I measured them all on the same night, but could not see Swift 108, which is supposed to be close by. 3260 has a star of mag 11.5 about 20" south, and Swift 108 is said to have an "eF * in contact." Since the position and description of Swift 108 agree closely with those of 3260, I judge them to be identical." As a result Dreyer didn't assign XI-108 an IC designation. Harold Corwin comments on inconsistencies in Swift's earlier discovery lists. Swift wrote "p[receding] of 2" in his 6th discovery list from Lowe in MNRAS and "f[ollowing] of 2" in Popular Astronomy. Then he included it again in his 7th discovery in MNRAS as the "sp of 2"! Assuming he found NGC 3260, it closely follows NGC 3258, though technically "sp of 3267" is correct.

400/500mm - 17.5" (3/28/87): very faint, small, oval. A mag 12 star is attached at the south end 0.4' from center. Forms a pair with NGC 3258 2.6' W. Member of the Antlia Cluster (ACO S636).

Notes by Steve Gottlieb