In 1847, at the age of 4, Mathias and his family left Prussia through the port of Antwerp, Belgium on the ship Epervier and headed for America. They arrived here on 22 Apr 1847 at the port of New York with possibly thousands of other immigrants. From there they traveled to and settled in the the Granville, Wisconsin area which is now the northern section of Milwaukee County, near where I live.
Back then it was probably mostly forests and grasslands. In his obituary in 1931, it states:
Mr. Firmenich came to Milwaukee in May 1847 and settled with his parents on a farm located in the wilderness 25 miles from that city. Coming in contact with Indians who the inhabited the region, he learned to weave baskets from ash wood, a hobby which he enjoyed until the time of his death.