Montgomery County’s superintendent on Thursday recommended approval of the county’s first public charter school, signaling that one of the nation’s marquee school systems is ready to accept such an experiment after years of resistance.

The new school, which could open in 2012, would represent a milestone for the Washington region. Until now, charter schools have proliferated mainly in the District.

“It’s a real breakthrough” for charter schools that “have been wrongly typecast as a remedy” only for the lowest-performing schools, said David Borinsky, president of the Maryland Charter School Network.

Advocates have said the logic of public charter schools — putting public money into the hands of private operators and creating more choices for parents — should work in any school district. Skeptics say that charter schools have yielded mixed results.

If approved by the county’s Board of Education, Community Montessori Public Charter School would open in Kensington to serve children from pre-kindergarten through third grade. The school would emphasize family education and social services.

While nearly 40 percent of the District’s public-school students go to charter schools, the affluent Washington suburbs have remained largely closed to the experimental schools. School board members in Northern Virginia and Montgomery have been skeptical of the need for alternatives, saying their systems already produce good results and offer a range of special programs and services.

Set to retire at the end of the month, Montgomery Superintendent Jerry D. Weast’s recommendation for the public charter school will be one of his last official acts at the helm of the 144,000-student school system. Previously, he had rejected some charter applications. His decision in this case comes as support for charter schools is taking root across the country and in Congress.

The school board will hear Weast’s recommendation Monday and is scheduled to vote July 7.

Buoyed in recent years by enthusiastic support from President Obama, the ranks of charter schools have swelled from about 2,000 a decade ago to more than 5,000 in the school year that is just ending. More than half of charter schools are in cities, but about one in five is in a suburb, according to the Washington-based Center for Education Reform.

At least a dozen states have rewritten laws to promote charter schools, in part to enhance applications for competitive federal grants. On Wednesday, the House Education and the Workforce Committee overwhelmingly approved a bill that would make it easier to replicate successful charter schools. It was a significant bipartisan advance in what has been a contentious, stop-and-go effort to rewrite the federal No Child Left Behind law.

Crossway Community, the nonprofit applicant for the Community Montessori school, already operates a preschool Montessori program on the Kensington site. The organization applied for a charter last year and was turned down. The State Board of Education ordered Montgomery to reconsider the application , but the county board in March rejected it again. The applicant then worked with school officials to improve its pitch.

Weast said the group “significantly strengthened the application, providing well-thought-through plans.”

Charter proposals are emerging elsewhere in Washington’s suburbs. A parent group in Clifton, an affluent, rural part of Fairfax County, is racing to complete an application deadline this month for a charter to replace an elementary school that the school board voted to close last summer amid community objections.

Applicants envision a school that would offer the county's only elementary International Baccalaureate program, as well as a focus on Chinese language and culture. Fairfax has no charter schools; in the entire state of Virginia, there are only four, despite efforts by Gov. Robert F. McDonnell (R) and the legislature to modify the approval process to make it easier to approve charter schools.

Maryland has more than 40 charter schools, about two-thirds of them in Baltimore. Frederick, Anne Arundel and Prince George’s counties all have charter schools.

Advocates say charter schools are taking root in suburbs such as Boulder, Colo., and Princeton, N.J. “In any district, urban or suburban, there are kids who fall through the cracks,” said Jeanne Allen, president of the Center for Education Reform, which promotes charter schools.

Weast’s recommendation followed the endorsement of a panel of educators, parents and business leaders that vetted the application.

The panel did not support a separate application for Seneca Creek Public Charter School, which proposed a school that would emphasize environmental science and outdoor education. The members raised concerns about the governance, finance, academic design and facilities.