List of smallest galaxies

M60-UCD1 is one of the smallest and densest known galaxies.

Below is a list of thesmallest known galaxies ordered by their diameters. Every galaxy on this list is below 20,000 light-years and they are sorted in sorted in ascending order.

List

List of smallest known galaxies

Name	Diameter (light-years)	Notes
Ursa Major III	9.6 [1]	Could be a star cluster instead of a galaxy.
M60-UCD1	158 ± 3.26 [2]
Andromeda XVIII	650 ± 48 [3]
GN-z11	4,000 ± 2,000 [4]
UGC 11411	~5,600 [5]
UGC 6541	~5,700 [6]
Messier 32	8,000 [7]
Sextans A	~8,000 [8]
NGC 4118	~8,100 [9]
Sextans B	~8,900 [10]
NGC 6822	~9,200 [11]
Messier 110	17,050 [12]
Small Magellanic Cloud	18,900 [13]

References

1. Devlin, Scot; Baumgardt, Holger; Sweet, Sarah M. (2025-05-01), "Reevaluating UMa3/U1: star cluster or the smallest known galaxy?", Monthly Notices of the Royal Astronomical Society, 539 (3): 2485, arXiv: 2504.21301 , Bibcode:2025MNRAS.539.2485D, doi: 10.1093/mnras/staf572 , retrieved 2025-12-14
2. Strader, Jay; Seth, Anil; Forbes, Duncan; Fabbiano, Giuseppina; Romanowsky, Aaron; Brodie, Jean; Conroy, Charlie; Caldwell, Nelson; Pota, Vincenzo (2013-08-14), "The Densest Galaxy", The Astrophysical Journal, 775 (1): L6, arXiv: 1307.7707 , Bibcode:2013ApJ...775L...6S, doi:10.1088/2041-8205/775/1/L6
3. Collins, Michelle L. M.; Chapman, Scott C.; Rich, R. Michael; Ibata, Rodrigo A.; Martin, Nicolas F.; Irwin, Michael J.; Bate, Nicholas F.; Lewis, Geraint F.; Peñarrubia, Jorge (2013-02-26), "A Kinematic Study of the Andromeda Dwarf Spheroidal System", The Astrophysical Journal, 768 (2): 172, arXiv: 1302.6590 , Bibcode:2013ApJ...768..172C, doi:10.1088/0004-637X/768/2/172
4. Oesch, P. A.; Brammer, G.; Dokkum, P. G. van; Illingworth, G. D.; Bouwens, R. J.; Labbe, I.; Franx, M.; Momcheva, I.; Ashby, M. L. N. (2016-03-01), "A Remarkably Luminous Galaxy at Z = 11.1 Measured with Hubble Space Telescope Grism Spectroscopy", The Astrophysical Journal, 819 (2): 129, arXiv: 1603.00461 , Bibcode:2016ApJ...819..129O, doi: 10.3847/0004-637X/819/2/129 , retrieved 2025-12-14
5. "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2025-12-14.
6. "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2025-12-14.
7. "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2025-12-14.
8. "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2025-12-14.
9. "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2025-12-14.
10. "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2025-12-14.
11. "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2025-12-14.
12. "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2025-12-14.
13. "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2025-12-14.