Although it was later, 1886, my grandmother's parents came from Prussia to New York. While not rich, they were well enough off to travel in second class and build a business when they got here. Did quite well in the Undertaking trade. While I have found many papers, most in German, and other documents, there's been nothing to give a reason for their leaving Prussia when they did.
It is something to ponder, that business as usual thing during a war that the North had going on. Had our ports not been blockaded, wonder if we'd have had some come to help our side?
Pam