Dennis Port is a census-designated place in the town of Dennis in Barnstable County, Cape Cod, Massachusetts. At the 2010 census, its population was 3,162.The Swan Pond River and Upper County Road demarcate Dennis Port's western border with West Dennis. The village of West Harwich lies directly to Dennis Port's east, with the border demarcated by the median of Division Street. To the north of Dennis Port is South Dennis.