Great CDV of armed and equipped soldier likely of Co. H (as seen by the hat brass) 121st NY Infantry from Herkimer County with a Little Falls backmark. And what a cravat on this guy... I'm including a photo for comparison of Clinton Beckwith of the 121st New York for uniform comparison.
There were other regiments from Herkimer County like the 34th NY and 152nd NY, but the photos I could find online show them in frock and sack coats.