Robert Grimes Davis was born 10 May 1819 in Honolulu, Honolulu County, Hawaii to William Heath Davis (1793-) and Hannah Kalikolehua Holmes (1796-) and died 5 March 1872 Honolulu, Honolulu County, Hawaii of unspecified causes. He married Harriet Swain Hammet (c1820-1858) 23 March 1843 in Honolulu, Honolulu County, Hawaii. He married Maria Kauapiiokamakaala Sumner (1825-1908) 1 August 1862 in Honolulu, Honolulu County, Hawaii.
Children
| Name | Birth | Death | Joined with |
| William Heath Davis (1846-) | |||
| Charlotte Holmes Davis (1852-1915) | 11 November 1852 Honolulu, Honolulu County, Hawaii | 17 August 1915 Honolulu, Honolulu County, Hawaii, United States | James Anderson King (1832-1899) |
| Charles Hammett Davis (c1850-) | |||
| Elizabeth Davis (c1854-) | |||
| Name | Birth | Death | Joined with |
| Robert Wyllie Davis (1859-) | |||
| Maria Davis (c1862-) | |||
| John S.K. Davis (1865-) | |||
Siblings
| Name | Birth | Death | Joined with |
| Robert Grimes Davis (1819-1872) | 10 May 1819 Honolulu, Honolulu County, Hawaii | 5 March 1872 Honolulu, Honolulu County, Hawaii | Harriet Swain Hammet (c1820-1858) Maria Kauapiiokamakaala Sumner (1825-1908) |
| William Heath Davis (1821-1909) | |||