The students, carrying signs that read “I [heart] charter schools,” packed the sprawling auditorium at the Ronald Reagan Building and International Trade Center. More than 1,000 children and teachers left school midday last month to attend a rally alongside leaders and consultants from the District’s charter sector. Chants ensued.

The speeches, calling on Mayor Muriel E. Bowser (D) to allow charter schools to use vacant city campuses, were impassioned.

“At the end of slavery, we were promised 40 acres and a mule, and that promise was never fulfilled,” said Shawn Hardnett, founder and executive director of Statesmen College Preparatory Academy for Boys, a public charter school that has struggled to find a permanent campus. “Now, we’re calling on Mayor Bowser for four acres and a school.”

It was the pinnacle of a citywide campaign imploring the District to remove empty school buildings from its inventory and give them to charter schools clamoring for adequate real estate. The rally, organized by the advocacy group DC Association of Chartered Public Schools, followed months of radio and web ads pushing the mayor to act.

Unlike traditional campuses, charter schools — which are publicly funded but privately managed — do not operate in taxpayer-funded facilities. Instead, the city allocates extra money to charter schools so they can secure facilities in an increasingly competitive private market or lease vacant government buildings. Charters receive about $3,300 per student for facilities.

But as the traditional public school system grows after years of declining enrollment and charters continue to open, some charters are scrambling for space.

The District’s charter school population is overwhelmingly black and Hispanic, and advocates have framed the quest for city properties as a civil rights issue, arguing that the city is denying children a quality education by refusing to let them use these government facilities.

There’s one significant disagreement framing the campaign: Charter advocates and city officials have a vastly different count of how many vacant buildings exist. Advocates say there are at least 10. The city tally? Just three. And D.C. officials are still determining if the District needs them.

“It is a set of facts that is irrefutable,” Deputy Mayor for Education Paul Kihn said. “And you have an advocacy group — a special interest group — that is promoting a set of facts that is false.”

Charter advocates insist that by using only a small part of some buildings, the city is pursuing a strategy of holding on to the structures — and keeping them out of the hands of charter operators. They point to the original Malcolm X Elementary, a shuttered campus in Southeast Washington, as an example of a building that should be leased to a charter. Kihn said that building is used by two city agencies, the Department of Employment Services and the Department of Parks and Recreation.

Hundreds of current and former school buildings exist in the District. The city operated a segregated school system for decades, with campuses for black children and white children serving the same grades in proximity to one another.

There are 215 buildings in the District used as public schools, both traditional and charter. The D.C. government owns 144 of those structures, leasing 30 of those campuses to public charter schools. The rest of the active school buildings in the city are owned or rented by charter operators.

Ramona Edelin, executive director of the DC Association of Chartered Public Schools, said high-performing campuses with long lists of students waiting for seats are unable to expand because they cannot find space.

Fledgling schools operate in church basements, or temporarily share space with other schools until they outgrow that space.

Five new charter schools are slated to open next fall, and it is unclear where they will locate.

“We would not want to be cynical by thinking the city is trying to thwart the growth of the charter sector by withholding the school buildings,” Edelin said. “But whether they intend to or not, that is the effect.”

Under federal law, charter schools in the District have the right to make the first offer on any surplus school campus the city owns. Preference is given to charter schools that are considered high-performing and financially sound.

If the city does not reach a deal with a charter school in six months, it can accept applications for the building from other organizations. In June, Bowser announced plans to lease the vacant Ferebee-Hope Elementary building — the first time in her nearly five-year tenure that she has proposed the possibility of leasing a city building to a charter. The city has not reached an agreement with a school to use the building.

The issue of school facilities has become charged in local education circles. Many proponents of the traditional public school system believe the city should hold on to school buildings, signaling it plans to invest in the growth of the system.

“People are very community-oriented, and it makes people lose hope when they give these neighborhood buildings away,” said Mysiki X. Valentine, a former D.C. teacher and campaign manager for the Fair Budget Coalition, a left-leaning D.C. advocacy organization. “Parents want choice, but when you continue to close neighborhood schools, you are taking away choice from families.”

D.C. Council member Vincent C. Gray (D-Ward 7), who led the city as mayor from 2011 to 2015, released more than a dozen school buildings to charters during his tenure. That has further fueled criticism that Bowser is hoarding facilities.

But Kihn said times have changed. Because D.C. Public Schools is growing, the city needs to keep its academic facilities, the deputy mayor said. But the city would consider sharing space with charter schools on traditional public school campuses that have capacity.

“The era of [D.C. Public Schools] being able to give over buildings to charters is over,” Kihn said. “I don’t see us being in a situation where we are going to decide whether we are going to give over lots of buildings to charters.”

Joshua B. Rales — president of the Norman and Ruth Rales Foundation, which helped fund the campaign urging the Bowser administration to release school buildings to charters — rejects assertions that the battle for space is a proxy war over whether charters or traditional public schools are more deserving of the buildings. The goal, he said, is to ensure that high-performing schools have access to facilities.

“The endgame,” he said, “is that every child should have access to an excellent school.”