I looked up each exchange that trades ETN. Here is a list of their country location. It looks like HitBTC is the only one with offices in the USA. The winner is Singapore with 4 then the Netherlands with 3.
Huobi - Singapore
KuCoin - Singapore
Liquid - Japan
Sistemkoin - Turkey
Tradeogre - Hidden/unknown
BitBNS - India
HitBTC - Europe and USA
Cryptomate - UK
CoinBene - Singapore
CoinBene Brasil - Brazil
CoinDeal - Malta
OEX - Singapore
CoinSpot - Australia
Artis Turba - South Africa
Bitalong - Unknown
BTCsquare - Spain
Crytrex - Italy
NEXT Exchange - Netherlands
SimpleSwap - Unknown
Indacoin - UK
Finexbox - Hong Kong
Bitladon - The Netherlands
Blockport- The Netherlands
