PublicGrades 9-12
Los Osos High School
6001 Milliken Avenue, Rancho Cucamonga, CA 91737-7709(909) 477-6900
Total Students2,759
Student/Teacher25.76:1
Math Prof.50.89%
Reading Prof.79.01%
School Information
Charter SchoolNo
Magnet SchoolNo
Virtual SchoolNo
CountySan Bernardino
School DistrictChaffey Joint Union High School District
Principal / AdminEric Cypher(909) 477-6900
Founded2002
Free/Reduced Lunch43.71% Eligible
Acceptance Rate100%
Student Demographics
White24.4%
Hispanic41.4%
Black5.9%
Asian22.9%
Native American0.3%
Pacific Islander0.1%
Two Or More4.9%
Gender Distribution
50.1%
49.8%
Male Female
Students per Grade
Grade 9721
Grade 10655
Grade 11685
Grade 12698
School Calendar 2026-2027
July 2026
Academic Schedule • 2026-2027
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Los Osos High School
Academic Calendar (2026-2027)
July 2026
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August 2026
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September 2026
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October 2026
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November 2026
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December 2026
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January 2027
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February 2027
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March 2027
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April 2027
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Key Dates & Holidays
Independence Day HolidayJul 3
First Day of School for StudentsAug 5
Labor Day HolidaySep 7
First Quarter EndsOct 2
Floating HolidayOct 5
Veterans Day ObservanceNov 11
Thanksgiving RecessNov 23
Second Quarter and First Semester EndDec 17
Winter Recess BeginsDec 21
New Year's Day HolidayJan 1
Martin Luther King Jr. Day ObservanceJan 18
Abraham Lincoln's Day HolidayFeb 8
Presidents Day ObservanceFeb 15
Third Quarter EndsMar 5
Spring Break BeginsMar 29
Spring Break EndsApr 1
Fourth Quarter and Second Semester EndMay 20
Memorial Day HolidayMay 31
Juneteenth HolidayJun 18
Key Dates & Holidays
2026-2027A Vibrant Learning Community in Rancho Cucamonga
This institution in the Chaffey Joint Union High School District fosters a dynamic environment for grades 9-12. Families often look for schools offering diverse athletic opportunities like basketball and soccer, alongside enriching academic pursuits such as STEM and robotics programs. Students may also find avenues to explore creative expression through the arts.
Engage and Explore
Our school is dedicated to student success both inside and outside the classroom. We encourage active participation in a wide range of activities. For detailed planning, parents can find the academic calendar conveniently located on this page.
Frequently Asked Questions
What extracurricular activities are available for students?
While specific programs vary each year, students often have access to clubs like robotics and athletics such as soccer. We recommend contacting the administration directly for the current list of activities.
How can I get involved in the school community?
There are many ways to contribute, from volunteering for school events to joining parent-teacher organizations. Check the website for upcoming opportunities and contact information.
Does the school offer college preparatory resources?
Yes, the campus provides guidance and resources to help students prepare for their post-secondary education, including college application assistance and career exploration.
What is the typical class size?
Class sizes can vary by subject and grade level. For the most accurate information regarding current class sizes, please reach out to the school's administrative office.
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