The St. Charles Avenue streetcar line, the oldest operating streetcar system in America, has been designated a National Historic Landmark, the U.S. Department of the Interior announced Tuesday.

The designation recognizes sites of historic importance to the entire nation, not just a particular community. The sites have a “high, not simply good level of historic integrity,” according to the Interior Department.

The new recognition specifically cites the St. Charles line’s place as the oldest operational street railway in the United States and its 35 “meticulously restored” arch-roofed, steel-bodied, green Perley Thomas streetcars as reasons for its designation.

“The line is representative of street railway systems and the urban growth patterns they engendered between the 1890s and the 1920s, when streetcars reached the height of their popularity in the United States,” the Interior Department said. “By facilitating outward mobility and suburbanization, streetcars strongly influenced the growth of cities and suburbs, today reflected in the urban character of many American cities, including New Orleans.”

Historic landmark designation does not result in any special funding, but owners of listed sites can apply for historic preservation grants.

Owners also are not bound by any new restrictions once their properties become listed, a National Park Service spokesman said.

The Park Service administers the National Historic Landmarks Program on behalf of the secretary of the interior. The program was created in 1935.

About 2,500 sites nationally are designated as National Historic Landmarks, including — in New Orleans — Jackson Square, the Cabildo, the Vieux Carre and the Garden District.

The St. Charles streetcar line, now the 54th designated landmark in Louisiana, has long been listed on the less exclusive National Register of Historic Places. That list includes about 90,000 sites.

Horse-drawn railway lines began operating in New Orleans, including on St. Charles Avenue, in the 1830s. The lines were electrified in the early 1890s. The Perley Thomas cars operating on the St. Charles line have run continuously since 1923.

The Park Service considers the age of a landmark and its ongoing use and contribution as factors for landmark designation, which follows an extensive process that often requires input from historians, architects and other groups.

The St. Charles Avenue Association spearheaded the effort to have the streetcar line listed, receiving support from the city, the Garden District Association, Iberia Bank and the Regional Transit Authority, which owns the line. The application process spanned 10 years and six St. Charles Avenue Association presidents, past President Ted Le Clercq said.

The Park Service recommended approval of the association’s 56-page application in May, and the Department of the Interior followed suit this month.

“It is a wonderful day for all of us who live in New Orleans,” Le Clercq said in a statement. “The green Perley Thomas streetcar and the St. Charles line symbolize some of the best of our city. They traverse a route, with a canopy from over 1,000 stately live oaks, through the history of New Orleans. Today, the city of New Orleans is the big winner with this recognition for the St. Charles line.”

The St. Charles cars join the San Francisco cable cars, listed in 1972, as the nation’s only moving landmarks.

The streetcar line was one of nine sites added Tuesday to the list of 2,544 national landmarks. The other eight are the Baltusrol Golf Club in Springfield, New Jersey; Brown Bridge in Rutland County, Vermont; Duck Creek Aqueduct in Metamora, Franklin County, Indiana; Eagle Island in Harpswell, Maine; the General Motors Technical Center in Warren, Michigan; the Frances Perkins Homestead in Newcastle, Maine; Lydia Pinkham House in Lynn, Massachusetts; and the Research Studio in Maitland, Florida.