The oldest recorded burial place for post–1786-division Chester county's dead and poor is Thompson's Burial Ground, in West Goshen Township. It was established around the time the County Seat was moved to West Chester in 1786 and was situated well outside the borough's northern limit east of what was then the intersection of the roads to Grove and the Indian King Tavern (today's Pottstown Pike). Those buried there included the poor, those who died in prison, and those who died of diseases. It was used sporadically until the early-mid 19th century.

For many years it laid largely forgotten, and the former Chief Burgess of West Chester John Thorp recalled that many bones were found when the road was cut through the hill there. It was noted in the 1870s that after heavy rains, skulls and other human remains would erode out of the hillside embankment and roll onto Pottstown Pike below.

As time wore on, the memory of Thompson's burial ground was almost lost, and when contractors expanding Saint Agnes Cemetery in 1900 were set to retrieve some fill dirt from the east side of the road, they found several sets of human remains. It was assumed at the time they were the remains of the native Lenape.

Upon learning of the discovery, mineralogist William W. Jefferis recalled that as, as a child in the first half of the 19th century, his father had taken him and a group of men to the "prison graveyard" there at the forks where a coffin had been found sticking out of the bank at the cemetery. "After digging the grave a foot deep," he remembered, "they came across a lot of human bones, including a skull. On digging deeper they found the remains of another body . . . . I was given a few bones and a hoe, and was told to dig a hole down in the wood and bury them, which I did in a hurry, for I was afraid."

Regrading the Pike eventually solved the issue of the remains eroding out of the hillside embankment. In 1895, the Chestnut Grove Cemetery Company purchased the site and adjacent land to establish its annex there. Though references to the burial ground exist on neighboring parcels' deeds, which often refer to it as the Thompson Burial Lot, no physical traces of Thompson's Burial Ground are thought to remain.