Who was the first Chasidishe Rabbi to settle in the USA? Where did he settle?
This article (PDF) says:
Earlier in the article, though, he mentions reports from 1893 in New York and 1894 in Baltimore of people giving out kameyos (amulets) and such; whether they were genuine rebbes or impostors, though, I don't know.
The first Chasidic Rebbe to come to America was R. David Mordecai Twersky who came in August of 1913.
The First American Chasidic Rebbe, I think would have to go to Grand Rabbi Pinchas Duvid Horowitz, the founder of the Boston Chasidim. He arrived in America via Israel and Europe in 1915.
The First American Chasidic Rabbi, would be Rabbi Abraham Ash,who served as Rabbi in New York from 1860. http://www.tzemachdovid.org/gedolim/jo/tpersonality/rjj.html