Brenna Swift, The Union Democrat

Sonora Elementary School is defying a regional trend for one simple reason: Its enrollment is increasing.

The school has about 40 more students than it did this fall, requiring it to add new staff members. Enrollment at most other schools Tuolumne and Calaveras counties has decreased, in some cases dramatically.

The new students are coming from other local districts as well as from outside Tuolumne County, said Sonora Elementary Principal Chris Boyles.

"We're proud," Boyles said. "Hopefully it's word of mouth, and parents feel a difference."

He identified the school's strongest priority as the safety of its students and praised its teachers' dedication to the community.

This year's modest enrollment gain came as a surprise to school officials. Sonora Elementary had planned on losing students, following a steady decline over the past several years, said Julie Barrington, the district's chief business official.

But as of Tuesday, Sonora Elementary's enrollment was 683, up from 645 on the first day of school. Sonora Elementary and Jamestown Elementary are the largest elementary school districts in Tuolumne County.

School officials keep close track of enrollment, since the state doles out funding based on the number of students at school on the average day. A gain of 10 students can translate into roughly $50,000 more for a school district.

Sonora Elementary opened up a new third-grade class this fall and, pending approval by the school board, will place aides in its three kindergarten classes - because teaching kindergartners is "like herding butterflies," Boyles said.

Larry Cope, director of economic development at the Tuolumne County Economic Development Authority, said he wasn't aware of any major new Tuolumne County employers that would account for a school enrollment spike.

He believes a number of factors, including movement between school districts, is likely at play.

Enrollment at Belleview Elementary School has also seen a modest increase over last year due to a larger kindergarten class. It now has about 130 students, compared with 100 last year.

Principal LaDeane Hansten attributed the gain to the popular Belleview Preschool program, which gets many families hooked on the school.

In Calaveras County, Mark Twain Union School District gained students and added more second- and fourth-grade classes this year.

Overall, though, Tuolumne and Calaveras counties shrank by about 3,000 school-aged students between 1996 and 2012.

Recent projections showed Sonora High may enroll around 900 students within the next few years, which would make it half the size it was in 2000.

Dramatic enrollment fluctuations have a stronger impact on small school districts like Tuolumne County's, since larger districts can more easily balance resources across multiple schools, said Sonora High Chief Business Official Kim Burr.