Henry P. Holmes was the youngest of eleven surviving children to David O. and Elizabeth Hensley Holmes of DeKalb County, MO.
Henry left home in approximately 1850 to join in the California gold rush. His oldest brother, William Livingston Holmes was then the first sheriff of Clackamas County, Oregon Territory. In 1855-56 Henry was a member of the Oregon Volunteers in the Indian War (Oregon).
In 1870 Henry was living in Chico, Butte, CA. In 1880 the census taker found him living in the household of his recently (1879) deceased brother Wm. L. Holmes household and his occupation is listed as carpenter.
In 1904, Henry applied for a pension from the US government citing his service in the Indian War. He died at the Old Soldier's Home (as it was then called) in the year of 1905.