The most famous and productive Epidote locality in the U.S. is Green Monster Mountain, on Prince of Wales Island, Alaska, where dark lustrous Epidote crystals have been found in very large crystals. Large dark green to nearly black crystals come from Garnet Hill, Calaveras Co., California; and good crystals from several deposits in Death Valley, Inyo California. Other important localities include Hawthorne and the Julie Claim, Mineral Co., Nevada; the Calumet Iron Mine, Chaffee Co., Colorado; the Oxford Quarry, Warren County, New Jersey; and the Belvidere Mountain quarries, Lowell/Eden, Orleans & Lamoille Cos., Vermont. The variety Hancockite comes from the Franklin District, Sussex Co., New Jersey. - See more at: http://www.minerals.net/mineral/epidote.aspx#sthash.GN6abqVs.dpuf
The above is this website's information about USA locations for epidote.