There is an excellent documentary called: The Jewish Americans, by PBS which I will link you to below.
People migrated here the same way other cultural groups had. Many who fled to the United Stated from 1654-1820 did so because of religious intolerance in other regions.
They primarily came from Brazil, Portugal, Spain, Bordeaux, Jamaica, England, Curacoa, Holland and Poland. The first Jewish communities in the United States were founded in NYC, Newport RI, Charleston, Savannah and Philadelphia.
Life in the United States wasn't much better towards the end of the 1800s. Antisemitism was pretty affluent and job seekers would not hire Jews (ads stated that only Christians should apply to jobs). Schools that eventually did accept Jewish students, did so on very low ?uotas like with African Americans.
One Jew was lynched (Leo Frank - the KKK movement was started because of this incident) and Henry Ford (yep same one glorified) started an antisemitic newspaper called "The Dearborn Independent" which was spread throughout 250,000 homes about "Jewish conspiracy theories. Hitler was actually in league with Ford believe it or not.
In any case: Since the Jewish community was not allowed to be a part of American culture, many people stayed within their own sections of town (this was true for many groups -- it's why New York City and other places have regions that are predominantly Chinese, Polish, Middle Eastern etc..) created schools, businesses, hospitals and universities in order to educate their children, support themselves and their families and help those in the community.
1820-1880 Second Wave of Jewish emigrants come from Germany brings 250,000 German Jews come to the United states.
1880 - 1920's A third wave of Jewish immigration follow son the heels of the Turkish Revolution and the collapse of the Ottoman empire. Sephardi Jews from the Balkans and Middle East begin to immigrate to the United States. They come from Turkey, Greece, and the lands that formed Yugoslavia.
Here is the time line:
Here is an excellent site for information on the subject:
Here are some videos on it: