Oklahoma State Archaeologist Kary Stackelbeck said 17 adult-size graves were located Friday and Saturday.
Additionally, the city announced Tuesday that four graves, two adult-size and two child-size, had been found.
The coffins, then the remains, will be examined to see if they match reports from 1921 that the victims were males buried in plain caskets.
“This is going to part of our process of discriminating which ones we’re going to proceed with in terms of exhuming those individuals and which ones we’re actually going to leave in place,” Stackelbeck said in a video statement.
The work, by hand, is still under way. The types of coffins and gender of the victims have not been determined, according to the city’s statement.
A violent white mob targeted Black people during the massacre, in which more than 1,000 homes were burned, hundreds were looted, and a thriving business district known as Black Wall Street was destroyed. Historians have estimated the death toll at 75 to 300.
Rumors persisted for decades of mass unmarked graves, but previous searches found no remains.
The current search began in 2020 in areas identified with ground-penetrating radar as possibly containing coffins and resumed last year, with nearly three dozen coffins found.
Fourteen sets of remains exhumed from those coffins were selected for DNA testing, and two had enough DNA to begin sequencing and start developing a genealogy profile.
The current search includes reexhuming and removing to a lab at the cemetery the other 12 remains in an effort to collect more usable DNA in an effort to eventually identify them.
All the remains will be reburied, at least temporarily, at Oaklawn, where the previous reburial was closed to the public, drawing protests from about two dozen people who said they are descendants of massacre victims and should have been allowed to attend.
The massacre wiped out generational wealth, and victims were never compensated, but a pending lawsuit seeks reparations for the three remaining known survivors. They are now more than 100 years old.