#1 Largest Private Schools in Ada County, ID
Cole Valley Christian Schools-Secondary
Christian school (nondenominational) · Grades Pre-K–12
1,263 students
Meridian, ID
B-Overall grade1,263 students16 students per teacher
2026 lists
Largest Private Schools in Ada County, ID
The private schools in Ada County, ID with the most students. Top 20 of 20 schools.
#2 Largest Private Schools in Ada County, ID
Bishop Kelly High School
Diocesan school · Grades 9–12
967 students
Boise, ID
BOverall grade967 students16 students per teacher
#3 Largest Private Schools in Ada County, ID
St. Ignatius Catholic School
Diocesan school · Grades Pre-K–8
428 students
Meridian, ID
B-Overall grade428 students18 students per teacher
#4 Largest Private Schools in Ada County, ID
St. Joseph's Catholic School
Diocesan school · Grades K–8
367 students
Boise, ID
B+Overall grade367 students15 students per teacher
#5 Largest Private Schools in Ada County, ID
Riverstone International School
Independent school · Grades Pre-K–12
349 students
Boise, ID
A+Overall grade349 students5 students per teacher
#6 Largest Private Schools in Ada County, ID
St. Marks Elementary School
Parish school · Grades Pre-K–8
323 students
Boise, ID
AOverall grade323 students14 students per teacher
#7 Largest Private Schools in Ada County, ID
Calvary Christian School
Christian school (nondenominational) · Grades Pre-K–8
223 students
Boise, ID
BOverall grade223 students13 students per teacher
#8 Largest Private Schools in Ada County, ID
Sacred Heart Catholic School
Diocesan school · Grades Pre-K–8
195 students
Boise, ID
BOverall grade195 students15 students per teacher
#9 Largest Private Schools in Ada County, ID
Calvary Meridian Prep Academy
Christian school (nondenominational) · Grades K–10
185 students
Meridian, ID
BOverall grade185 students15 students per teacher
#10 Largest Private Schools in Ada County, ID
St. Marys School
Diocesan school · Grades Pre-K–8
109 students
Boise, ID
A+Overall grade109 students6 students per teacher
#11 Largest Private Schools in Ada County, ID
One Stone
Independent school · Grades 9–12
87 students
Boise, ID
BOverall grade87 students36 students per teacher
#12 Largest Private Schools in Ada County, ID
Boise State University Trio Upward Bound
Alternative school · Grades 9–11
80 students
Boise, ID
A-Overall grade80 students6 students per teacher
#13 Largest Private Schools in Ada County, ID
Boise Valley Adventist School
Seventh-day Adventist school · Grades Pre-K–8
75 students
Boise, ID
BOverall grade75 students13 students per teacher
#14 Largest Private Schools in Ada County, ID
Montessori Academy
Montessori school · Grades Pre-K–6
62 students
Eagle, ID
B+Overall grade62 students10 students per teacher
#15 Largest Private Schools in Ada County, ID
Joshua Institute Academy
Special education school · Grades 3–12
56 students
Meridian, ID
BOverall grade56 students8 students per teacher
#16 Largest Private Schools in Ada County, ID
A Child's Choice Montessori School
Montessori school · Grades Pre-K–6
52 students
Meridian, ID
AOverall grade52 students6 students per teacher
#17 Largest Private Schools in Ada County, ID
Kidz Connection Montessori
Montessori school · Grades Pre-K–5
30 students
Boise, ID
AOverall grade30 students2 students per teacher
#18 Largest Private Schools in Ada County, ID
Eagle Adventist Christian School & Preschool
Seventh-day Adventist school · Grades Pre-K–8
23 students
Eagle, ID
AOverall grade23 students5 students per teacher
#19 Largest Private Schools in Ada County, ID
Rose Hill Montessori School
Montessori school · Grades Pre-K–6
22 students
Boise, ID
A-Overall grade22 students9 students per teacher
#20 Largest Private Schools in Ada County, ID
The Preschool & Kindergarten @ten Mile Christian
Early childhood program · Grades Pre-K–K
20 students
Meridian, ID
B+Overall grade20 students13 students per teacher
From official public records, updated October 2026.