This weekend, in Bristol, Conn., a Little League team from Southeast D.C. will take the field and make history.

The Mamie Johnson Little Leaguers will be the first predominantly black team and the first team from east of the Anacostia river to represent the nation’s capital at the Little League Mid-Atlantic Regionals. If they succeed, they will head to the ultimate contest, the Little League World Series.

At home, their city is experiencing dramatic demographic shifts. Affluent newcomers have transformed much of the District, and many longtime residents — particularly in the heavily African American neighborhoods of Southeast — feel left out or threatened by the changes, especially as gentrification creeps across the river. Tensions over the pace and nature of development have been building.

Amid all this, the 11- and 12-year-old Mamie Johnson kids have become a source of pride for their Ward 7 community. What’s more, their success has seemed to captivate all of D.C.

“It’s good for the neighborhood and good for the city,” said Greg Roberts, the district administrator for D.C. Little League and a longtime advocate for youth baseball. “They give the city a lot of hope.”

For more than 30 years, Little League teams from the city’s wealthy Northwest enclaves have claimed the D.C. championship. Ward 7, which lies almost entirely east of the Anacostia, didn’t even have a consistent league until Mamie Johnson was founded just four years ago. The team has 12 players; 11 are black and one is white.

“It’s a big win for the community,” said Stephen Makle, whose son Ian is on the team.

Mamie Johnson has won support across D.C. — even from the teams it beat en route to the city title.

After its victory, it began raising money for the estimated $10,000 needed for the 333-mile road trip to the regionals. A little over a week later, it had nearly double that, said league president Keith Barnes. Sister leagues — Northwest, Capitol City and Capitol Hill — all pitched in. More than 250 people have donated — $25 here, $100 there, Barnes said.

“It’s just one baseball family to another,” he said.

All season, the team has brought Ward 7 together. By the end, residents who didn’t even have kids on the team were showing up for practices and games to root them on.

The night of the city championship, a hot and rainy Tuesday in July, fans packed the Nationals Youth Baseball Academy. They filled the stands, from the bleachers to the upper deck — and it was clear for whom most were rooting.

“South-South-Southeast!” went one call. It was a din of air horns, sirens and rocks shaking around water bottles.

“It was the most people I’ve seen in a crowd,” said 12-year-old Joshua Young, one of the players.

As fans urged them on, Joshua and his 11 teammates came from behind twice and won. When they made the last out and the players tossed their gloves in the air like graduation caps, the crowd rushed the field to celebrate with them.

Even though Mamie Johnson went to the championship game last year and narrowly lost, the players felt opponents often underrated them.

“They think that because we’re African American, coming out of Southeast, we only play basketball or football,” said Rocco Gilbert, 12, who made the championship game’s last out.

As relative newcomers to D.C. Little League, they faced skepticism from more established teams.

“People want to take us down, they want to tear us down,” Joshua said. “Other teams see us as a joke.”

After the city tournament, as the kids celebrated and parents snapped pictures, Post Malone’s “Congratulations” blared from a portable speaker.

“We showed D.C. that the boys in Southeast have the best baseball in the city,” said Tawny Simmons, who describes herself as the “team mom.”

In the week since they won, the Little League team, named for Mamie “Peanut” Johnson, the only woman to pitch in the Negro leagues, has received pro athlete-level attention — TV and radio interviews, a visit to Mayor Muriel E. Bowser’s office, an invitation from Del. Eleanor Holmes Norton to tour the Capitol and, soon, a ceremonial resolution courtesy of D.C. Council member Vincent C. Gray (D-Ward 7).

“It’s crazy,” 12-year-old Langston Speed said. “I didn’t know we were making that much history. It means a lot because we work so hard every day.”

Gray was an accomplished ballplayer himself — Major League teams recruited him, he said — and he’s been eagerly awaiting a city champion from his home ward.

“I couldn’t be more excited than at this point,” Gray said. “It is a dream come true.”

As mayor and council member, Gray helped bring the Nationals Youth Baseball Academy to Southeast in 2014. Mamie Johnson Little League was created the same year and the two organizations partnered. The academy’s facilities and education programming filled a void, and it became a neighborhood institution.

“If we didn’t have the Nats Academy, we wouldn’t have any of this,” said Stephen Showalter, 12, a Mamie Johnson player.

Parents say the academy creates a sense of community and encourages kids to succeed on and off the field.

“It’s that village-level reinforcement,” said Jerome Young, father of Joshua. “You have not just us as parents saying it, but that coach, that mentor.”

The Mamie Johnson players have also made lifelong friends, said coach Curtis Banks, who grew up in Southeast. Banks, fellow coach Raphael Lockett and Barnes — all volunteers — see themselves as father figures, or maybe cool uncles, and say the team’s family atmosphere is partly why so many in the city have gravitated toward them.

Stephen was out of town and missed the city title game, but after the team won, Banks and the players gathered in the parking lot and called their missing teammate on video chat to deliver the good news.

“We’re all in the parking lot jumping up and down,” Banks said. “To me, they weren’t friends anymore, they weren’t teammates anymore, they’ve now become family. It was something I’ll never forget.”

Among all the celebration, it’s easy to forget the team’s toughest games may still lie ahead, at the regional tournament, which begins Sunday and could run through the week.

After their successful fundraising, Mamie Johnson Little League chartered a bus to Connecticut and will make the drive through five states this weekend. And, when they get there, the team from Ward 7 will be playing for their entire city.

“It feels like we did something for our team and our community,” Langston said. “And we’re ready to do something for D.C. as a whole.”