Where to Find and Catch Mismagius
From Pokemon Go Wiki
Mismagius are found and captured in Nest and Habitat locations.
Nests
Mismagius Nests are locations that consistently spawn Mismagius.
Habitats
Mismagius Habitats are spawn locations where Mismagius is likely to be encountered, but not guaranteed the way a Nest is.
Additional Tips and Information
Best Nests
If you know a really good nest or any of the nests above is really good, list them here: