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