Seaman - Same Surname - Various Origins
Just because two people share the same surname doesn't mean they are related. In the United States and Canada, there are many different, unrelated families that share the surname of Seaman.
It is quite certain that the largest group of related Seamans are those descended from Capt. John Seaman (1610-1694) who came to Massachusetts colony from England in 1630. Captain John was married twice. He first married in 1644 to Elizabeth Strickland. Captain John and Elizabeth had four sons and one daughter. Captain John Seaman next married a Martha Moore in 1655. They had four sons and seven daughters.
The details above are from "The Seaman Family in America as Descended from Captain John Seaman of Hempstead, Long Island" by Mary Thomas Seaman - published in 1928. This work, in a modified format, has been made available online here.
It is little wonder that this group of Seamans are the most common in the US and Canada considering their early presence in the English colonies and the large base of eight sons and eight daughters that was laid down by Capt. John. This website deals with the descendants of a single grandson of Capt. John Seaman - the descendants of this one grandson, Caleb Seaman, number well over 3000!
But, Capt. John's descendants are by no means the sole source of the Seaman surname in the New World.
Over the years many families have immigrated to the United States and Canada. Some of these families came with the surname of Seaman, some anglicized their non-English surnames to Seaman. I've run across some of these lines while researching my own family members.
Below are bits and pieces of what I've seen, hopefully it will help someone in tracking their family history.
In early Pennsylvania there were two notable groups of Seamans. One (Noah) from England and the other (Johann Ludwig Seaman/Saeman) from Germany. And, of course, there were likely a few descendants of Capt. John mixed in as well.
There was also a Seaman family from England that settled in Massachusetts colony. Thomas and Susannah SEAMANS lived in Swansea, Massachusetts in 1687, and this is the birthplace of their 11 children. Thomas' three sons (Thomas, John, and James) moved to Scituate, Rhode Island between 1740 and 1746. The spelling of their surname has varied over the generations but many use spellings of SEAMON or SEAMAN today.
Yet another couple with the Seaman surname came from County Cavan, Ireland. They settled in Shawville, Clarendon County, Province of Quebec, up the Ottawa River from the city of Ottawa, in 1833. John SEAMAN had been a Captain in the military in Ireland. In Shawville they raised 10 children.
In the early 1800's the Seaman name was once more introduced from England - this time to Prince Edward Island in Canada. Some of this family's history is documented here.
The above are just a few examples of the various Seaman families that exist. There are new immigrants to the US and Canada everyday - some of them are named Seaman as well! Good luck in tracing your origins!