Brevet Major Augustus Plummer Davis (May 10, 1835 – May 21, 1899) was a Union Army officer during the American Civil War. He is best known as the founder of the Sons of Union Veterans of the Civil War.
Davis was born in Gardiner, Maine and was the son of Anthony and Mary Davis. His father was of Welsh extraction. He had ancestors who served in the American Revolution and the War of 1812.
At the age of 14 Davis left home and travelled to San Francisco as part of the 1849 California Gold Rush. His dreams of finding a fortune did not come to pass and he returned his career as a sailor in 1850. He worked on various ships over the next five years. He enlisted in the Royal Navy for four years during the Crimean War. He was discharged from the Royal Navy in 1860 and returned to his family in Maine later that year.
Shortly after the attack on Fort Sumter in April 1861, Davis volunteered to serve in the 11th Maine Volunteer Infantry Regiment and was elected as captain of Company F on May 11, 1861. Shortly afterwards, the 11th Maine was sent south to serve with the Army of the James.
In April 1862 Davis was detached from the 11th Maine and detailed as Provost Marshal of the division commanded by Major General Silas Casey. He was wounded in action at the Battle of Fair Oaks and spent several weeks recovering in the hospital.
On March 7, 1863, Davis resigned from the Army and returned to Maine. Soon after his arrival in Maine, on April 24, 1863, he was appointed as Provost Marshal for the 3rd District of Maine and re-commissioned as captain. He held this position until he was honorably discharged on August 15, 1865.
On June 22, 1867 Davis received a brevet (i.e. honorary promotion) to the rank of major to date from March 15, 1865.