The Terrell House is fenced off and boarded up. Only a marker outside the property suggests the house’s significance, and little has been done to restore the property. (Ricky Carioti/The Washington Post)

Cloistered behind a chain-link fence, the boarded-up house at 326 T St. NW is a duplex sliced in half, abandoned and seemingly forgotten. But the marker outside indicates it shouldn’t be.

Deemed historic in 1975, this former home of civil rights activist Mary Church Terrell, and her husband, Judge Robert Terrell, had been preserved to help tell a narrative of the city’s past. But now it tells a story from the present: of a city undergoing a seismic demographic shift and struggling to keep its rich history alive.

The home’s owner, Howard University, has halted its plans to rehabilitate the Terrell House as a local museum and community space. That movement lost its momentum during the Great Recession, and there has been little effort to resuscitate it since.

So the Terrell House sits, a strange, decaying relic of another time, in the middle of a block lined with newly painted Victorian homes updated with features like exposed brick and granite countertops.

“Almost every house on this block has been renovated, except for that one,’’ said Brian Baylor, a 27-year-old paralegal who has lived in the neighborhood since birth. “No one wants it to go because it’s historic. But it is an eyesore, and it should be restored. It should be a tourist attraction.”

Map of the 163 District houses in the Inventory of Historic Sites, with a fact or two about each.

Baylor knows the broad strokes of the Terrell family history: Mary Church Terrell was the first black woman appointed to the school board and led the charge to integrate city restaurants. Husband Robert Terrell was a Harvard graduate and the first black municipal judge in the District. The duplex looks sliced in half because the other side of the dwelling burned in a fire long ago, and the Terrells’ half was saved by the firewall.

Such historic knowledge is becoming more elusive as the city continues to swell with young newcomers — and old houses get demolished for condos. In the past decade, the District’s preservation officials have been attempting to counter the trend. They’ve established heritage trails in historically black neighborhoods such as Deanwood and U Street and collected oral histories of elderly residents. Since 2001, the office has added 15 houses to the city’s historic register, which now totals 163 historic homes. None had been designated in the previous decade.

“We don’t want to fall into a situation where people who live here don’t have a sense of where they live or their own history,” said David Maloney, the District’s preservation officer.

The current register features mostly embassies and private homes, mostly in wealthy neighborhoods, that were chosen for their architectural significance. No more than five or six are vacant, Maloney said.

Preservationists have become more interested in identifying the homes of distinguished city residents that may also tell the story of a neighborhood. For example, the home of Eugene Allen, an African American butler for 34 years in the White House, is now being considered for historic designation. Allen, the subject of a 2008 Washington Post article, was the inspiration for a character played by Forest Whitaker in the 2013 movie “The Butler.”

But the danger is that those houses — like the Terrell House — may not be in pristine condition. And once designated as historic, they become very difficult to tear down, however blighted.

The Terrell House presents a conundrum for LeDroit Park residents living along T Street, in Ward 1, a rapidly gentrifying area that saw one of the nation’s largest gains in white population between 2000 and 2010, according to census data.

Sandwiched between the U Street Corridor and Howard University, LeDroit Park was once a gated, all-white neighborhood. Howard students continually protested and tore down the gates, prompting its integration. By the 1940s, it had become home to prominent black figures such as jazz great Duke Ellington and Ralph Bunche, the first black man to receive a Nobel Peace Prize.

Residents today largely embrace that history, but opportunities to share it are limited. The historic Howard Theatre has reopened as a music venue, but the former home of prominent educator Anna J. Cooper, who was one of the first black women to obtain a doctorate, is privately owned by a family.

The Terrell House may be the neighborhood’s last shot at a historic gathering place to honor its illustrious past.

“This house could be the way to tell a story about the influential African Americans not just in the city, but in the country,” said Yayo Grassi, a caterer who said he was the only white person on the block when he moved there in 1989. “It’s sad.”

The house was built in the 1890s. Over the next decade, Mary Church Terrell became a part of the women’s suffrage movement at the request of Susan B. Anthony, a founding member of the NAACP, and of a prominent black sorority, Delta Sigma Theta.

She penned columns about black soldiers and the plight of black women in both black publications and white publications, including The Post.

When she was in her 80s, she was among the plaintiffs in the court case District of Columbia v. John R. Thompson Co., which led to the desegregation of restaurants in the District in 1950. A light-skinned woman dressed elegantly in skirts and gloves, Terrell was sometimes mistaken for being white. That helped her gain access, according to her step-grandson, Ray Langston.

“She would tell these stories about going in and sitting at these restaurants,” Langston said. “At the end, she’d say, ‘Now, it wasn’t so bad serving a colored person, was it?’ People would get furious.

“When I was a kid, she used to take me to walk these picket lines at Hecht’s and Woolworth’s,” Langston said. “I didn’t want to go, but she’d say we couldn’t go to the beach unless we picketed first.”

Langston is 74. He’s the only family member left who has any memory of his grandmother, and his memory is growing foggy.

His grandmother died in 1954. Her will guaranteed that Howard University could take possession of the home after the death of her only daughter, Phyllis. The university assumed the title in 1998.

Langston said his mother hoped the university would use the home to house college students who couldn’t afford tuition. Instead, the condition of the house became so decrepit that the District considered razing the structure in 2002.

The university and local historians worked to save it from demolition, then immediately began dreaming up new uses in meetings with the community, said Maybelle Taylor Bennett, the university’s community liaison.

Over time, more white residents began attending the meetings. They appeared at first to know little of the history of their new neighborhood, but they came to embrace it.

“Gentrification has been an issue here, and now we have residents who move here that don’t understand the history of the neighborhood, and what makes it great,” said Paul Herron, 42, who is white. He moved to T Street with his wife, Dina Lewis, in 2000. “It’s a history we’ve come to love.”

Eventually, the university started a foundation to fix up the house and began searching for grants to install a museum to honor the Terrell family.

Langston approved and offered his parents’ book collection with autographs from former president Ulysses S. Grant and author Harriet Beecher Stowe. The third floor would be dedicated to research on LeDroit Park. A Web site was built. The estimated cost of the renovation was $1.7 million.

In 2009, the group spent $563,000 to patch holes in the roof and to restore the masonry. But money for the renovation dried up during the recession as grant applications were denied, Bennett said. The project’s coffers have dwindled to about $10,000, he said.

Meanwhile, Howard has been grappling with fiscal challenges of its own, shedding staff positions as it attempts to reorganize.

“Everything has kind of cooled off as the university has turned toward issues that are really, really pressing,” Bennett said. “I understand why, even though this project is my heart.”

LeDroit Park residents have sometimes been frustrated with Howard’s stewardship. At one point, there was a clamor about the university’s abandonment of properties along a city block while it sought to expand its hospital. In 1998, the university worked with Fannie Mae to renovate the houses, which helped prompt the neighborhood’s revival.

Now, the neighborhood is concerned about the Terrell House. But so is the university, which takes its duty to honor Terrell’s will seriously, Bennett said.

“Our job is to keep the story of the Terrell family alive,” she said. “There’s been no place in the city to tell their story, and we think it should be in their home.”