COLUMBIA, S.C. — Essie Mae Washington-Williams, the mixed-race daughter of onetime segregationist senator Strom Thurmond who kept her parentage secret for more than 70 years, has died. She was 87.

Vann Dozier of Leevy’s Funeral Home in Columbia said Washington-Williams died Sunday. A cause of death was not given.

Washington-Williams was the daughter of Thurmond and his family’s black maid. The identity of her famous father was rumored for decades in political circles and the black community. She later said she kept his secret because, “He trusted me, and I respected him.”...