Answer:
American Jewish history commenced in 1492 with the expulsion of Jews from Spain. This action set off a period of intense Jewish migration. Seeking to escape the clutches of the Holy Inquisition, some Jews in the sixteenth century sought refuge in the young Calvinist republic of The Netherlands. A century later, hundreds of their descendants crossed the ocean to settle in the new Dutch colony of Recife in Brazil, where Jewish communal life became possible for the first time in the New World. When Portugal recaptured this colony in 1654, its Jews scattered. Refugees spread through the Dutch Caribbean, beginning fresh Jewish communities. A boatload of about 23 Jews sailed into the remote Dutch port of New Amsterdam and requested permission to remain. This marked the beginning of Jewish communal life in North America.
Colonial Jews never exceeded one tenth of one percent of the American population, yet they established patterns of Jewish communal life that persisted for generations.
First, most Jews lived in cosmopolitan port cities like New York and Newport where opportunities for commerce and trade abounded, and people of diverse backgrounds and faiths lived side by side.
Second, many early American Jewish leaders and institutions were Sephardic, meaning that their origins traced to the Jewish communities of the Iberian peninsula. Sephardic Jews maintained cultural hegemony in Jewish life into the early nineteenth century, although by then Ashkenazi Jews, meaning Jews who traced their origins to Germany, had long been more numerous.
Third, Jews organized into synagogue-communities. Savannah, Charleston, Philadelphia, New York, and Newport each had one synagogue that assumed responsibility for the religious and communal needs of all local Jews.
The American Revolution marked a turning point not only in American Jewish history, but in modern Jewish history generally. Never before had a major nation committed itself so definitively to the principles of freedom and democracy in general and to religious freedom in particular. Jews and members of other minority religions could dissent from the religious views of the majority without fear of persecution. Jews still had to fight for their rights on the state level, and they continued to face various forms of prejudice nationwide. However, many Jews benefited materially from the Revolution and interacted freely with their non-Jewish neighbors. Having shed blood for their country side by side with their Christian fellows, Jews as a group felt far more secure than they had in colonial days. They asserted their rights openly and, if challenged, defended themselves both vigorously and self-confidently.
In the nineteenth century, American Jews, seeking to strengthen Judaism against its numerous Christian competitors in the marketplace of American religions, introduced various religious innovations, some of them borrowed from their neighbors. Young Jews in Charleston, dissatisfied with the "apathy and neglect" they saw manifested toward their religion, somewhat influenced by the spread of Unitarianism, fearful of Christian missionary activities that had begun to be directed toward local Jews, and, above all, passionately concerned about Jewish survival in a free society, created the breakaway "Reformed Society of Israelites for Promoting True Principles of Judaism According to Its Purity and Spirit." This was America's first Reform congregation, with an abbreviated service, vernacular prayers, and regular sermons. Traditional congregations also "Protestantized" some of their practices, introducing regular English sermons and more decorous modes of worship.
Meanwhile, communal leaders, led by the Traditionalist Jewish religious leader of Philadelphia, Isaac Leeser, emulated and adapted Protestant benevolent and education techniques--Sunday schools, hospitals, the religious press, charitable societies, and the like--in order to strengthen Judaism in the face of pressures upon Jews to convert. Among other things, Leeser produced an Anglo-Jewish translation of the Bible, founded a Jewish publication society, and edited a Jewish periodical, The Occident and American Jewish Advocate, which attempted in its pages to unite the diverse voices of the American Jewish community. He also rallied his community to respond to incidents of anti-Jewish persecution around the world.
Even though Ashkenazic Jews outnumbered Sephardic Jews as early as 1720, the first German Jewish immigrants joined Sephardic synagogues rather than founding their own institutions. As poverty, persecution, and political disillusionment swept through Central Europe in the first half of the nineteenth century, German and Polish Jewish immigration to America swelled. Distinctly German-speaking Jewish institutions multiplied. Jews also moved beyond the Eastern seaboard at this time, seeking opportunities in the frontier communities of the Midwest, South, and West.