There was an article in letters to the Editor of the Cape Cod Times if Dennis Port is one word or two words. The editor stated that the Cape Cod Times uses Dennis Port (two words) and The Register also uses the two word version. The Town, State and Federal government all use the official and historical spelling Dennis Port. The internet also uses the two word version. The Dennis Historical Society and the Dennis Historical Commission and the History of Barnstable County all use the two word version. The below response is from, Phyllis Horton, one of the most knowledgeable historians on the Town of Dennis.
There will still be people that will disagree and say Dennis Port is one word and the debate will continue, as Buzz Lightyear said, “to infinity and beyond”.