CHICAGO – If not sidelined by a broken ankle, Katherine Adamski might never have studied at the same high school as singers Donny and Marie Osmond, tennis star Andre Agassi, artist Jamie Wyeth, actress Jessica Alba and teenage fantasy author Christopher Paolini.

The 18-year-old Adamski wanted an alternative to regular high school and she found it at the American School, housed in a two-story, brown, brick building in Lansing, Ill.

There are no ivy, grassy quad, sports fields, stage or even classrooms. Founded in 1897, it is a correspondence school.

The private, nonprofit institution still communicates with its approximately 40,000 students the way it did when the telephone and the automobile were new-fangled inventions. It receives and returns about 750,000 exams a year by mail from students who live across the country and around the world.

A proliferation of online courses has fueled rising enrollment in distance education, which includes online and correspondence schools, by about 15 percent a year, officials said. Students now total about 8.5 million.

“Online learning and its ubiquitous, cheap and fast technology all provide more convenience to adult learners,” said Michael Lambert, executive director of the Distance Education and Training Council in Washington, D.C.

Still, the American School has no plans to drastically alter the way it does things. Mail bins stacked with exams are stamped when received and then distributed to instructors who specialize in specific subjects.

Thirty instructors sit in long rows of desks in a large room, using red pens to grade exams and make handwritten, personalized comments to students.

The school was founded in Boston on the idea that education should not be just for the elite.

It meant that factory and farmworkers, maids and seamstresses should have the same opportunity to get an education as wealthy people.

“The idea was to bring education to the masses, the working masses, who didn’t have leisure time or money to go to school,” said Roberta Allen, executive vice president of the American School.

The Armour Institute of Technology (now the Illinois Institute of Technology) invited the school to move to Chicago in 1902. It relocated from Hyde Park to Lansing in 1996.