Among the earliest graveyards in Collin County, this cemetery began in 1852 when Dr. Lillie was buried on land belonging to his uncle William Forman. A Kentucky native, Forman came to Texas about 1850 and bought 640 acres in 1851 from Sanford Beck. Lillie's death led pioneer settlers to meet and decide the location of a graveyard. The owners of four sections of land that converged together promised equal portions for the cemetery, although most of the earliest graves are on Forman land. By the 1870s the Forman Family Cemetery was combined with cemetery tracts purchased by the local Masonic and Odd Fellows' lodges. In the 1890s a group of local women organized the Ladies Mutual Cemetery Association to maintain the site, beautified the grounds, provided a pavilion, and doubled the cemetery's size during their nearly 40 years of tenure. By 1907 adjoining tracts of land had been bought by the Mutual Cemetery Association, Woodmen of the World, and Knights of Pythias organizations. The Plano Mutual Cemetery Association was formed in 1928 and continues service to the cemetery. Buried here are many early pioneers and their descendants, war veterans, and elected officials.