In September 1874, Henry L. Norman, "once a Methodist preacher in London," arrived in New York City as a missionary for Islam. While it is likely that there had already been Muslim proselytizers in the U.S.--all of whom were either slaves or former slaves--Norman was probably the first Muslim convert proselytizer in the country, and he most likely reached out to white Americans.
For a brief discussion of Norman and the people among whom he most likely found an interested audience, see my "Islam and 'Scientific Religion' in the United States before 1935" Islam and Christian-Muslim Relations 22 (2011): 311-328
