List of largest nebulae

Below is a list of the largest known nebulae so far discovered, ordered by actual diameter.

This list is prone to change because of inconsistencies between studies, the great distances of nebulae from our stellar neighborhood, and the constant refinement of technology and engineering.

Nebulae have no standardized boundaries, so the measurements are subject to revision.

[2] Farina et al. 2019 table 5 has an extensive compilation of Lyman alpha nebulae around quasars.

[1] For now this list contains only the largest ELANs, with sizes larger than 300 kpc.

NGC 604 , one of largest nebulae ( H II region ) is located in the Triangulum Galaxy (viewed by the Hubble Space Telescope ).