The only physical remnant of the Post Oak community, this cemetery began as the burial ground for the family of Isham McMillin, who acquired land in this part of Bell County in 1855. The oldest marked grave, that of McMillin's daughter Elizabeth, dates from 1857. Several graves, marked by piles of stones or illegible markers, may predate Elizabeth's burial.
A large proportion of graves mark the burial sites of infants and children, testament to the harshness of frontier life as Anglo settlers moved into the area. Buried here are members of a number of pioneer families, including the Edwards, Fulton, Sinclair and Ezell families. Isham McMillin, who died in 1861, is buried here, as is another McMillin daughter, Mary (1852-1864).
In 1873, Sarah McMillin sold two acres of land to the deacons of Mountain Home Baptist Church for the purpose of building a church and schoolhouse. The Mountain Home church came to be called Post Oak Baptist Church , as did the school and the community. The school consolidated with the Center Lake School District in 1916 and later became part of the Holland public school system. The Post Oak Baptist Church continued to meet until a 1952 fire destroyed the church building and the congregation disbanded.
Burials continued to take place in the graveyard, and the Post Oak Cemetery Association, organized in 1951, cares for the cemetery, which stands as a reminder of early Bell County settlement.