Heinrich Julius Schrader

Can any help me trace Heinrich Julius Schrader born June 9, 1827 in Braunschwei, Germany. His father was a blacksmith. At 21 years of age he left Germany for New York City. Upon arriving in NYC he immediately left for Chicago and then on to Milwaukee for the 4th of July celebrations. In Milwaukee he married Margaretha Leuring born Sept. 6, 1834 in Hannover, Germany. They eventually homesteaded a farm outside of Northfield, Minnesota.

I have all the information inside the USA but no information from Germany. I know he had a brother that came to the USA after him but they could never find each other. I do not know what ship he came to the USA on and am only guessing it was 1847 because they said he was 21.

Any help the list could give me would be greatly appreciated.

Gail Schrader