Shockoe Bottom in Richmond, Va., has been listed by a national preservationist group as endangered because of a proposal to build a stadium there. The site was a former hub of the U.S. slave trade. (AP Photo/Tvnewsbridge via National Trust for Historic Preservation)

Underneath a Richmond neighborhood along the James River, preservationists say, lies the history of this city’s crucial role in the national slave trade — and it’s about to be buried further.

The National Trust for Historic Preservation announced Monday that the Shockoe Bottom neighborhood is urgently threatened by a proposal by Revitalize RVA, a plan by the mayor to build a baseball stadium and other businesses in an area where slaves were once penned and sold. The National Trust listed the neighborhood as one of the 11 most endangered places in the country, a list it has been compiling annually for more than 25 years.

“I would put right at the top of that list, from a significance standpoint and an urgency standpoint, Shockoe Bottom,” said Stephanie Meeks, president of the trust. The issue is politically charged in Richmond, she said, but the site is nationally significant. “It’s part of our nation’s story that needs to be remembered, needs to be documented and appropriately commemorated. We see this as a site of conscience and one that shouldn’t just be quickly covered up with a baseball stadium.”

Richmond Mayor Dwight C. Jones (D) has argued that the area could be revitalized with a stadium, hotel, grocery store and other development that would provide much-needed jobs and spending by tourists. He had also proposed using city and state money to commemorate some relics of the slave history in the area, such as a notorious jail.

Business leaders in the community recently announced their strong support of development.

A spokeswoman for the mayor did not respond to requests for comment Monday. The plan, which the mayor recently withdrew as he sought to shore up City Council support, would include archaeological work in the area.

Rob Nieweg of the National Trust said that plan was not adequate because “it’s fundamentally monitoring what comes up when the construction begins . . . an archaeologist standing at the edge of the pit watching to see what the backhoes pull up.”

The area’s history wasn’t well known until recent years, when groups such as the Richmond City Council Slave Trail Commission began investigating records and digging in. They learned that in the mid-1800s, the city was the second-busiest slave-trading site in the country, with hundreds of thousands of people bought and sold. They uncovered evidence of infamous sites such as Lumpkin’s Jail and the jail where Solomon Northup, whose memoir was the basis of the Oscar-winning movie “12 Years a Slave,” is believed to have been held after he was kidnapped.

Supporters of development have said that private investment would help ensure that those sites are appropriately commemorated, with a pavilion designed around Lumpkin’s Jail, for example, that would let visitors see into the archaeological dig. The buildings are long gone, some under fill dirt from nearby Interstate 95, some paved over as parking lots.

“The most challenging thing about this place is that what we’re trying to preserve is buried under the ground,” Nieweg said.

The neighborhood was also listed as endangered this year by Preservation Virginia.

The National Trust also warned that the following 10 sites, noteworthy for things such as their architecture, natural beauty or cultural history, are threatened by forces ranging from earthquakes to demolition plans: Battle Mountain Sanitarium in South Dakota, Bay Harbor’s East Island in Florida, Chattanooga State Office Building in Tennessee, Frank Lloyd Wright’s Spring House in Florida, Historic Wintersburg in California, Mokuaikaua Church in Hawaii, Music Hall in Ohio, the Palisades in New Jersey, the Palladium Building in Missouri and Union Terminal in Ohio.