Water Department crews were digging a new drainage ditch in the rear of William Dick Elementary School, located on the 2400 block of West Diamond Street, around 2:00 p.m. when the workers happened upon coffins.
Orange lines mark the coffins and splintered wood could be seen evenly spaced and in a row.
Seven coffins were found and the Philadelphia School District says human remains were also unearthed.
As a result of the unusual find, officials with the Department of Licenses and Inspections as well as the Historical Society have been called in to trace the origin of the discovery.
According to Findagrave.com, 24th and Diamond used to be the Odd Fellows Cemetery. It was established in 1849.
The city bought the land in 1951 to build the Raymond Rosen Housing Project.
The school district says William Dick Elementary was built three years later.
Muhammad Abdur-Rauf used to live off Diamond Street as a boy. He remembers when the land around William Dick Elementary was a cemetery.
"I was 10 years old when they started digging the cemetery up. They killed our playground," he said.
Findagrave.com says some of the graves were moved to Mount Peace Cemetery in Philadelphia and Lawnview Cemetery in Montgomery County, but Wednesday's discovery reveals not all the coffins were removed.
"It is what it is," said Dwight Upshaw. "They didn't take the time to take the gravestones up. Everybody in a hurry today."
The school district says school will be in session. A perimeter fence will keep students away.
License and Inspections is investigating the find, but they have not responded to calls from Action News.