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