When Robert Barrows married Ruth Bonum at Plymouth on 28 November 1666 (Plymouth VRs, p. 665) he joined quite the extended kinship network in Plymouth at the time. Ruth was the daughter of George and Sarah (Morton) Bonum. Sarah was the daughter of George and Julianna (Carpenter) Morton. The Carpenter-Morton-Cooper extended family included:
- Alice Carpenter, Julianna's sister, who married first Edward Southworth, then Gov. William Bradford. She was the mother of both Constant and Thomas Southworth as well as Bradford's three youngest and surviving children.
- Agnes Carpenter, sister of the Alice and Juliana married Dr. Samuel Fuller of the Mayflower.
- Mary Carpenter, another sister, lived at Plymouth and died unmarried.
- Priscilla Carpenter, another sister, married first William Wright and then John Cooper. John's sister Lydia married Nathaniel Morton, the son of George and Julianna and the secretary of Plymouth Colony for most of his life.
- Patience Morton, sister of Nathaniel and Sarah, married John Faunce, had eight children and then married Thomas Whitney.
By his second marriage to Lydia Dunham, Robert then expanded his kinship to all the Dunhams. It not surprising to see these names as witnesses on deeds and other documents throughout the last part of the 17th century.