There is some confusion to the Dunhams. Older genealogies have the Dunhams coming from Mass. with the Dorchester Colony. More modern research shows the family seems to become affiliated with these separatists in South Carolina.
There are several spellings Donnom, Dunnam and Dunham.

John Dunham- [source Liberty County Land Deeds] was born 1750 in South Carolina and moved to Georgia. Died 1816 in McIntosh. I believe he is buried at the Midway Church- not sure. wife Sarah Clancy

Had William, Jane, Jacob Hendricks, Mary, Sarah, George Washington, Charles and Ann Dunham children. All born in Liberty or McIntosh Counties.

Jacob Dunham [1774-1832] was know to be a lay preacher to the slaves up and down the Georgia Coast. Yes, he was a slaveholder. He recorded to be buried near Sunbury. He married Mary Baisden [1783-1864].  They produced several children. Of interest is Sarah who married Joseph Baisden [cousin?] and 2nd married Richard Wickham Gould.

Mary Dunham married Charles Simmons Trezevant.

The Trezevants were an allied family of the Gignilliats. There are several marriages between these families. Apparently, the Gignilliats came shortly after the Rev. War and the Trezevants some time in the early 19th century.

Margaret  Gignilliat Trezevant's town house in Darien was burned with the rest of the town in spite of a Union Colonel's attempt to post black troops to protect a widows home. Another Union officer countermanded the order and the home was looted.

Charles Trezevant's younger brother James P Trezevant ended up a hero of the Texas Revolution. Was captured and escaped a massacre- one of only 8 surviviors. Fought at the battle of San Jacinto. Lived in Mississippi and Louisiana and practiced law. The youngest sibling was George Trezevant- he became a physician

 There were many plantations over the years. Mentioned in a manuscript by Charlotte Trezevant Gignilliat [sister to above James and Charles] are the following plantation names. I would love to know more about these properties. Charlotte was the wife of Norman Page Gignilliat- that's right another cousin

"The Ridge"- somewhere near Ridgeville
Contentment
Arcdoch- in McIntosh- owned by Gignilliat Family
Windy Hill- I believe this was in Glynn County
Oak Grove- this was in McIntosh
There was another property near Woodville or the name was Woodville was a
summer home as Windy Hill was unhealthy during the summer. It was primarily
a rice plantation- malaria.