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