September School Photo - Winter Trip in Estes Park

Best Boulder County Private High Schools (2026)

For the 2026 school year, there are 10 private high schools serving 1,049 students in Boulder County, CO.
The top-ranked private high schools in Boulder County, CO include Transitional School, Tara Performing Arts High School, and September School.
The average acceptance rate is 62%, which is lower than the Colorado private high school average acceptance rate of 83%.
25% of private high schools in Boulder County, CO are religiously affiliated (most commonly Other and Church of Christ).

Top-Ranked Boulder County Private High Schools (2026)

School
Location
Quick Facts
Dawson School
Dawson School Photo - Dawson School sits on a beautiful 107-acre campus, serving families from Boulder, Longmont, Broomfield, Erie, Lafayette, Louisville, and the surrounding area
(13)
10455 Dawson Drive
Lafayette, CO 80026
(303) 665-6679
Gr: K-12 | 477 students Avg. class size: 15 students Sports: 11 | Extracurrculars: 7 Tuition listed
Fusion Academy Boulder County
Alternative School
168 Centennial Parkway, Suite 100
Louisville, CO 80027
(877) 673-8893
Gr: 6-12 Avg. class size: 1 student Tuition listed
September School
September School Photo - Winter Trip in Estes Park
(1)
96 Arapahoe Ave.
Boulder, CO 80302
(303) 443-9933
Gr: 9-12 | 24 students Avg. class size: 8 students Sports: 1 | Extracurrculars: 8 Tuition listed
Shining Mountain Waldorf School
Shining Mountain Waldorf School Photo - Movement
Special Program Emphasis
(17)
999 Violet Avenue
Boulder, CO 80304
(303) 444-7697
Gr: PK-12 | 200 students Avg. class size: 20 students Sports: 4 | Extracurrculars: 6 Tuition & acceptance rate listed
Tara Performing Arts High School
Tara Performing Arts High School Photo - Ninth grade: History through Art in New York
Special Program Emphasis
4180 19th St
Boulder, CO 80304
(303) 410-4510
Gr: 9-12 | 55 students Tuition & acceptance rate listed
Transitional School
Alternative School (Church of Christ)
14780 N 107th St
Longmont, CO 80504
(303) 776-6841
Gr: 6-11 | 9 students
Crossroads School
Crossroads School Photo - Crossroads 2025 graduates
Alternative School (Christian)
833 15th Ave.
Longmont, CO 80501
(303) 709-9881
Gr: 6-12 | 50 students Extracurrculars: 1 Tuition listed
Hillside School
Special Education School
6620 Gunpark Rd
Longmont, CO 80301
(303) 494-1468
Gr: 2-12 | 57 students Avg. class size: 4 students Tuition listed
Temple Grandin School
Temple Grandin School Photo - TGS Trades Classroom
Special Education School
(2)
3131 Indian Road
Boulder, CO 80301
(303) 554-7363
Gr: 6-12 | 17 students Avg. class size: 6 students Extracurrculars: 4 Tuition & acceptance rate listed
Watershed School
Watershed School Photo
Alternative School
(8)
5405 Spine Rd
Boulder, CO 80301
(303) 440-7520
Gr: 6-12 | 102 students Sports: 4 | Extracurrculars: 6 Tuition listed
[+] Show Closed Private Schools in Boulder County, Colorado

Boulder County Private Schools (Closed)

School
Location
Quick Facts
3046 11th St
Boulder, CO 80304
(303) 443-4965
Gr: PK-K | 34 students
1818 Centennial Dr
Louisville, CO 80027
(303) 665-5511
Gr: NS-K Tuition & acceptance rate listed
1011 Dry Creek Dr
Longmont, CO 80503
(303) 682-0102
Gr: NS-K
1941 Terry St
Longmont, CO 80501
(303) 651-3780
Gr: K | 3 students
5524 Baseline Rd
Boulder, CO 80303
(303) 494-3100
Gr: PK-K | 33 students Acceptance rate listed
8979 Nelson Rd.
Longmont, CO 80503
(303) 678-9335
Gr: 6-12 | 18 students Avg. class size: 10 students Tuition & acceptance rate listed
833 15th Ave
Longmont, CO 80501
(303) 776-5677
Gr: 1-12 | 129 students
419 Main St
Lyons, CO 80540
(303) 823-9629
Gr: NS | 38 students
Our Saviors Lutheran School (Closed 2012)
(Wisconsin Evangelical Lutheran Synod)
1219 W 17th Avenue
Longmont, CO 80501
(303) 776-1688
Gr: NS-1 | 11 students Avg. class size: 3 students Tuition listed

Overview

This County (Boulder County)
This State (CO)
# Schools
12 Schools

Student Body:

# Students
1,049 Students
28,973 Students
% Average Students of Color
13%
25%

Academics and Faculty:

# Teachers
204 Teachers
3,034 Teachers
Average Student-Teacher Ratio
6:1
10:1
% Average Faculty w/Advanced Degree
59%
56%
Average Class Size
9 students
13 students
Average Number of AP Courses
16 courses
12 courses
Average SAT score
1385
(Out of 1600)
1268
Average ACT score
31
(Out of 36)
25

Tuition and Acceptance Rate:

Average Yearly Tuition Cost
$23,920
$16,491
Average Summer Program Cost
$1,500
$2,471
Average % on Financial Aid
31%
33%
Average Financial Aid Grant
$8,163
$8,504
Average Acceptance Rate
62%
83%
Average Endowment Size
$4 million
$30.76 million

Students by Ethnicity:

0.28
0.58
# American Indian Students
4 Students
269 Students
% American Indian Students
n/a
1%
# Asian Students
54 Students
909 Students
% Asian Students
5%
3%
# Hispanic Students
65 Students
2,802 Students
% Hispanic Students
5%
9%
# Black Students
24 Students
1,099 Students
% Black Students
2%
4%
# White Students
1,030 Students
17,821 Students
% White Students
85%
61%
# Hawaiian Students
n/a
37 Students
% Hawaiian Students
n/a
n/a
# Two or more races Students
n/a
n/a
% of Two or more races Students
n/a
n/a
# Others Students
36 Students
6,384 Students
% of Others Students
3%
22%
All Ethnic Groups

Extracurriculars and Sports:

Average Number of Extracurriculars
5 extracurriculars
9 extracurriculars
Average Number of Sports
5 sports
8 sports

Frequently Asked Questions

What are the top-ranked private high schools in Boulder County, CO?
The top-ranked private high schools in Boulder County, CO include Transitional School, Tara Performing Arts High School, and September School.
How many private high schools are located in Boulderunty?
10 private high schools are located in Boulderunty.
How diverse are private high schools in Boulderunty?
Boulderunty private high schools are approximately 13% minority students, which is lower than the Colorado private school average of 25%.
What percentage of private high schools are religiously affiliated in Boulderunty?
25% of private high schools in Boulderunty are religiously affiliated (most commonly Other and Church of Christ).
Which private high schools in Boulderunty are often viewed compared to one another?
Popular comparisons of private high schools in Boulderunty include: Transitional School vs. Dawson School, Transitional School vs. Crossroads School

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