Henry David CAWTHORN was the eldest, and only surviving son, of John Henry CAWTHORN and Maria MILNE. He was born in London in 1816 and emigrated in 1818 with his parents, maternal uncle George MILNE and his father's cousin John FORD. They travelled on a convict ship, Lord Melville to Van Diemen's Land where his father obtained a large grant of land on the Derwent River at Macquarie Plains. Initially they probably lived at New Norfolk where they had taken over the ferry. They later moved up river to their property Arundel, adjacent to his cousins, the Barkers.
In 1839, David married Ruth FINCHER and they had six children, all born at Macquarie Plains and christened at St Marys Gretna.
In 1850, nine months after his father died, David died from cancer, leaving his wife to manage a heavily mortgaged property and a family of small children. At some point her mother-in-law moved next door to live with her daughter at the Barker property.