The statue of Douglass was dismantled and taken on Sunday from Maplewood Park, a site along the Underground Railroad where Douglass and Harriet Tubman helped shuttle slaves to freedom.
The statue was found at the brink of the Genesee River gorge about 50 feet (15 meters) from its pedestal, police said.
In a statement provided to the Rochester Democrat & Chronicle, police said the statue, after it was removed, "had been placed over the fence to the gorge and was leaning against the fence."
The statue was abandoned an estimated 50 feet away from where it had stood, according to the report. There was damage to the base and a finger.
President Trump condemned the vandalism on Monday, saying in a tweet: "This shows that these anarchists have no bounds!"
In Rochester on July 5, 1852, Douglass gave the speech “What to the Slave is the Fourth of July,” in which he called the celebration of liberty a sham in a nation that enslaves and oppresses its black citizens.
To a slave, Douglass said, Independence Day is “a day that reveals to him, more than all other days in the year, the gross injustice and cruelty to which he is the constant victim.”
Douglass died in 1895 and was laid to rest at a cemetery in Rochester.
The Associated Press contributed to this report.