Archaeologists at the Oregon Zoo have uncovered the remains of nine unidentified people.
Zoo officials say the remains are likely from residents of a poor farm run by Multnomah County until 1911. Hillside Farm was located in a portion of Washington Park where the zoo is today.
Crews halted construction of a stormwater retention system when they discovered the remains several weeks ago.
Heidi Rahn is director of the zoo's bond program. She says human remains were also discovered during 2008 construction.
"So we proceed with caution generally when we're digging around here because we are aware of the history of the site, but we don't have any precise locations of the former cemeteries."
Rahn says a new education center slated for 2016 will include exhibits that discuss the history of the zoo's land.
The excavated remains, she says, will be buried at a nearby site on zoo grounds.
This story originally appeared on Oregon Public Broadcasting.