NGC 4618 is a distorted barred dwarf galaxy in the constellation Canes Venatici. The galaxy is formally classified as a Sm galaxy, which means that its structure vaguely resembles the structure of spiral galaxies. The galaxy is sometimes referred to as a Magellanic spiral because of its resemblance to the Magellanic clouds. One supernova has been observed in NGC 4618: SN 1985F (type type Ib).

300/350mm - 13.1" (4/12/86): moderately bright, fairly large, faint elongated halo with large brighter core which appears displaced towards the north. This is an unusual one-armed spiral galaxy with a more extensive halo on the south side. Forms a pair with NGC 4625 8.3' NNE. IC 3668 is a knot in the southern arm.

400/500mm - 18" (5/15/10): This is a very unusual, asymmetric Arp galaxy with a single massive arm (similar to NGC 4027). At 220x it appeared bright, fairly large, obviously irregular, with a slightly elongated main body ~2'x1.5', extended 4:3 SW-NE. Within the main portion of the galaxy a brighter, elongated bar was visible, roughly 1.5'x0.5'. The central bar, though, is displaced to the NW side of entire glow as extending mostly to the south side is a faint, beefy arm that often appears detached and barely connected on the east end of the central region. This broad arm winds counterclockwise from east to south roughly 100° with IC 3668, the brightest region or knot near the south end of the arm, ~1.8' from the center of the bar. This single arm increases the overall size to ~3'x2'. IC 3369 refers to the brighter SE portion of the spiral arm.

900/1200mm - 48" (4/7/13 and 4/19/17): fascinating one-armed asymmetric spiral (Arp 23). At 488x the core region is offset to the north side and appeared extremely bright, irregular, elongated 5:3 SW-NE, 1.6'x1.0'. A prominent, thick, knotty arm is attached on the northeast end and sweeps counterclockwise to the south and then west. It includes a small, round knot (listed in NED as infrared source SSTSL2 J124136.60+410900.6), 0.8' due east of center. IC 3669 is a brighter arc or section of the arm, about 1' southeast of the core. IC 3668 appears as a bright, elongated HII region(s) at the south end of the arm (1.7' south of center), ~20"x10". The arm continues to rotate towards the north on the west side of the galaxy, but this feature has a very low surface brightness and ends roughly west of the core. Only a faint, diffuse glow with no structure was seen to north of the core. The total size of the galaxy extended 3.5'x2.5'. NGC 4618 forms a pair with NGC 4625 8.3' NNE. Interestingly, both galaxies have single prominent arms, though the arm in NGC 4625 was more subtle visually. Member of the CVn II Group, with brightest member M106.