WArkansas River ValleyWBlackstone ValleyWCentral Naugatuck ValleyWChamplain ValleyWFox Valley (Illinois)WHudson ValleyWLower Connecticut River ValleyWMenomonee ValleyWMississippi embaymentWMissouri River ValleyWMohawk Valley regionWNew River ValleyWOhio Valley in KentuckyWParadise Valley (Montana)WPark Valley (Arizona)WQuabbin–Swift River ValleyWRed River ValleyWSalt River ValleyWSanta Clara River ValleyWSusquehanna ValleyWTualatin ValleyWWest Branch Susquehanna ValleyWWillamette ValleyWWood River Valley
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W
W