ST. PAUL — The National Park Service has designated American Indian burial mounds in St. Paul as historic after decades of eligibility.

The Park Service recently added six burial sites in Indian Mounds Park to the National Register of Historic Places. The mounds along the Mississippi River are at least 2,000 years old. They’ve been eligible for the register since the early 1980s.

The six mounds were part of an original group of 18 and are the last remaining in the Twin Cities. Thousands more burial sites near the Mississippi and Minnesota rivers have been destroyed by settlement. The mounds have been protected by state law since 1976.

A landscape architect for the city says the new designation could improve access to grant money for park improvements.