A: There were many American ports in operation in the 1870s, but the major ones seeing the most arrivals were Baltimore, Boston, New Orleans, New York and Philadelphia. It's impossible to guess which port your husband's relatives were most likely to arrive at—although German arrivals tended to favor the ports of Philadelphia, New York and Baltimore—but your best course of action is to check published indexes first, such as the Germans to America series, and then ports that are indexed for the 1870s. These would include Baltimore, Boston and Philadelphia. The port of New York is not indexed for this time period, and if they came through New York, they would have been processed at Castle Garden, located in Battery Park, since Ellis Island did not open as an immigrant receiving station until 1892. No special records would have been created; you'd still be searching for the passenger arrival list. If your husband's grandfather and his parents became naturalized citizens, check for naturalization records, which might give you arrival information, depending on when they became citizens.