The harmless species, found on offshore islands in western Lake Erie in Ohio and Ontario, is the 23rd species to be de-listed after recovery and conservation efforts, a U.S. Department of the Interior release said.
"Today the Lake Erie watersnake joins species such as the bald eagle, the American alligator, and the peregrine falcon that have rebounded from the threat of extinction and no longer require the protection of the Endangered Species Act," Secretary of the Interior Ken Salazar said.
"These species -- and the hundreds of others whose extinction has been prevented by the Act -- are living testimonies to its ability to bring species back from the brink by protecting them and conserving and restoring their habitat," he said.
The Lake Erie watersnake was listed as a threatened species in 1999 because of intentional killing and loss of its Lake Erie shoreline habitat to development.
About 300 acres of inland habitat and 11 miles of shoreline have been protected for the snake since it was listed, the release said.