A noose was found on the National Mall early Saturday evening, U.S. Park Police said.
It was found near the National Gallery of Art hanging from a light post near the intersection of Third Street and Pennsylvania Avenue.
Police are still investigating the incident.
Tourists found a noose last month on the floor of the National Museum of African American History and Culture. A few days earlier another noose had been found on the grounds of the Hirshhorn Museum, which features contemporary art and culture.