Sign up for Chalkbeat Philadelphia’s free newsletter to keep up with the city’s public school system.Philadelphia Principal KaTiedra Argro has spent years trying to boost enrollment at Philadelphia’s storied High School for Girls.She’s been so successful that Girls High now has a new challenge: classrooms so packed that 55 students are squeezed into one history section.“It’s been overwhelming,” said Jamie Liu, 14. In her freshman World History class, extra tables and chairs crowd the room. She’s mostly still able to learn, she said, but it’s loud and sometimes distracting with more than 50 students regularly in attendance.This year’s freshman class at Girls High has about 250 students, three times bigger than the one three years ago. Since becoming principal in 2024 amidst a sharp enrollment decline, Argro has reenergized Girls High’s recruitment by visiting dozens of elementary and middle schools each year, and advertising the school on social media. Enrollment remains below where it was three years ago, with 603 students this school year, but Argro said she is seeing her work pay off in the larger freshman class.But the calculation the district uses to assign staff budgets to schools hasn’t kept up with the growth. The teachers union contract limits class size to 33 students, but Argro said she wasn’t given approval to hire enough staff for all the students who ultimately showed up. The result is jam-packed classrooms where staff say it’s difficult to ensure every student is getting the attention they need.“We went out and got the kids,” said Argro, who took over as principal in 2024. “When the babies actually did show up, it was like, oh, what are we going to do?”On Wednesday, district officials gave Argro permission to hire an additional teacher. That will enable class sizes to come down to the maximum of 33 students, she said. Argro said district officials have been responsive to the schools’ needs and helpful.But to social studies teacher Chris Canary, adding one teacher isn’t enough. One section of the African American history course he teaches has 54 students. A few weeks into the semester, Girls High canceled another class he was supposed to teach, AP macroeconomics, so that he could take on an additional section of African American history, which is a district graduation requirement. The AP class was small, with only nine students. But canceling it seemed like the wrong approach, he said.“We were starting to hit a groove and it was going well,” said Canary. “Instead of offering us the full staffing that we need, they turn to, let’s cut programming instead.”Argro said students in the macroeconomics class will be offered opportunities to enroll in AP courses or dual enrollment during the spring semester.District underestimated freshman enrollmentGirls High is one of several competitive magnet schools in the city that students must apply to, get accepted into, and then commit to attending. But during previous years, students who initially accepted offers regularly didn’t show up, or soon transferred out, Argro said. Enrollment changes are common at the beginning of the year at many schools as families adjust to new communities and often long commutes. But to increase enrollment, Argro has developed a strategy to decrease no-shows: She invites families to an event for accepted students in March to showcase the school. Then, she hosts a summer orientation.For Argro, it’s about helping Philadelphians “remember the reputation the school once had.” As one of the oldest all-girls schools in the country, Girls High reportedly once had 2,000 students enrolled. Principal KaTiedra Argro has reinvigorated Girls High’s recruitment by visiting dozens of elementary and middle schools each year.But Argro’s recruitment success meant that during the district’s spring budgeting process, officials underestimated how many students would enroll, according to a statement from district spokesperson Naima DeBrest. The freshman class in particular was around 20 students larger than expected, she said. Arthur Steinberg, president of the Philadelphia Federation of Teachers, said classes that are slightly over the limit are typical at the beginning of each school year. But having more than 20 additional students in several classes is extreme, he said.The union contract, which sets the class size limit, also gives the district time to add staff at the beginning of the school year based on enrollment. All classes are supposed to be under the limit by the end of September.Argro said she was glad Girls High received approval to hire a new teacher ahead of that deadline. She hopes one will be able to start as soon as next week.Still, all that has still left students in extremely crowded classrooms several weeks into the school year.“Sometimes we can’t get the teacher’s attention, or it gets like too many people are talking,” said Nayeli Tavera, 15, whose AP African American history class has 46 students. “It gets too rowdy.”Rebecca Redelmeier is a reporter at Chalkbeat Philadelphia. She writes about public schools, early childhood education, and issues that affect students, families, and educators across Philadelphia. Contact Rebecca at rredelmeier@chalkbeat.org.