Served as Thurston County coroner for two terms and at the time of his death in 1903 was the deputy coroner. Born in Ohio in 1830, he moved with his family to Iowa at the age of 10. Aaron outlived three wives. His first wife, whom he married in 1851, died in 1855. They had 2 daughters. His second wife, by whom he had 3 children, died in 1861. In 1866 he married Mary Bricker. Their only daughter, Mabel Blanche, died in 1885 at the age of 15 and is buried in this cemetery.
Aaron Hartsock was not an early settler of this area. In 1874, he finally heeded the advice of his older brother, Gallatin Hartsock, and made the journey west. Gallatin Hartsock had crossed the Oregon Trail in 1852 and had taken out a Donation Land Claim on the southwestern edge of what was then called Rutledge Lake. Gallatin's son-in-law was Urban East Hicks and Rutledge Lake is now called Hicks Lake. Gallatin's daughter and Aaron's niece, Emma Hartsock Horton, lies nearby.
Gallatin lived in the Lacey area, but Aaron decided to settle in Olympia. Although Aaron was a carpenter by trade, he was chosen to oversee farming on the Puyallup Indian Reservation about two years after his arrival. Upon his return to Olympia he worked in several stores before becoming the coroner.
Aaron was a valued member of the Masonic Lodge like many of his neighbors in this area. When he died in 1903, his funeral was conducted in accordance with Masonic tradition. He was well-liked in Olympia and his obituary noted that, "Mr. Hartsock's long residence in Olympia and his sterling qualities brought him a wide circle of friends throughout the county and there are few of those who have lived here any length of time but they were acquainted with him."
Aaron's wife, Mary, died in 1898 after a long illness. Her obituary observed that she had been a devout Christian. "During her last illness and up to the time of her death she often spoke of her assurance of the joys of a future life with the Lord's redeemed ones." Not only did Aaron outlive 3 wives, at the time of his death in 1903, only 2 of his daughters were still living.