Where to Find and Catch Loudred
From Pokemon Go Wiki
Loudred are found and captured in Nest and Habitat locations.
Nests
Loudred Nests are locations that consistently spawn Loudred.
Habitats
Loudred Habitats are spawn locations where Loudred 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: