Gov. Kathy Hochul traveled to the territory of the largest Native tribe in New York State Tuesday to apologize for the atrocities committed at the long-closed Thomas Indian School, where Native children were systematically stripped of their culture and language and subjected to abuse.

The school opened in 1855 on Seneca Nation territory as the Thomas Asylum for Orphan and Destitute Indian Children, and, unlike the many federally operated boarding schools that housed Native American children, it was overseen by state authorities.

“But instead of being a haven for orphaned children, it became a place of nightmares, a place some would call a torture chamber,” Ms. Hochul said. “A site of sanctioned ethnic cleansing.”

A federal reckoning of the legacy of these boarding schools for Native American children began a few years ago, and led to an apology from then-President Biden last year. But the trauma inflicted by New York State at the Thomas Indian School, which took a strikingly similar approach to the forced assimilation of Native children in schools run by the U.S. government, has largely remained in the shadows.

On Tuesday morning, Ms. Hochul’s appearance on the Seneca Nation’s Cattaraugus Territory, about an hour south of Buffalo, thrust the school’s history into the spotlight.