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About Us

The Chaffey Joint Union High School District serves the communities of Ontario, Montclair, Rancho Cucamonga, and portions of Fontana, Upland, Chino, and Mount Baldy. With over 25,000 students, the District is the fourth largest high school district in California. It has eight comprehensive high schools, a continuation high school, an online high school, a community day school, an adult school, and alternative programs. The District offers a wide variety of instructional options that provide a quality education for each student, every day. The District's well-prepared, dedicated, and highly qualified teachers and support personnel are second to none.
The Chaffey Joint Union High School District Board of Trustees are steadfast in the belief that "Nothing is more important than student learning and their achievement."
Our daily purpose encompasses our commitment:
"To provide student learning, and ultimately their achievement, of the prescribed curriculum that takes place in the classroom under the direction of the teacher." The Chaffey District supports this daily act. We realize that our efforts uniquely influence the future of our community and of this nation, and we are passionate about doing whatever it takes to prepare students to be successful and contributing citizens of the 21st century.
The Chaffey District has provided a quality education for high school students in the area since 1911. As the District continues to grow and progress, we are poised to meet the challenge of providing the finest quality education possible for every student. 
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All CJUHSD students will graduate ready for college and careers.

Recent News

Summer School

View the 2023 Summer School calendar and bell schedule.
WeTip - Be the solution


Be the Solution. If you have information regarding crime or misconduct at your school, call WeTip anonymously.

The Chaffey District Cares

The Chaffey District cares about your mental well-being. We partner with community agencies and mental health professionals to provide support to our students and staff. If you, or someone you know, is in crisis please contact the Community Crisis Response Team (909) 421-9233 - Click 'Read Full Story' for more information.

Upcoming Events

School Facts

  • 78% of Los Osos High School graduates meet the University of California and California State University A-G admissions requirements, making it a leader in San Bernardino County.
  • 98% of freshmen at Los Osos High School complete their first year of high school on track to graduate.
  • The CJUHSD has been named a Top Workplace by the Press-Enterprise and Inland News Group.
  • 2500 Advanced Placement exams are administered to students at Los Osos High School annually.

Principal's Message

Eric Cypher
Grizzly Nation,  
We are rapidly approaching the end of the school year with our last day being on May 25, 2023.  In addition to that being the last day of the school year, it is also the day of our graduation ceremony!  Seniors will arrive on campus at 5PM with doors to the stadium opening at 5:15 PM. The ceremony will begin at 6:30 PM in our Grizzly Football Stadium.  For the ceremony we will not permit balloons and noise makers into the stadium.  This ceremony is momentous occasion and we look forward to honoring all our seniors, thank you in advance for following this guideline. 
Finals are also around the corner and will be taking place May 23rd – 25th.  Please note that Seniors will take their 1st and 2nd period finals on the 19th & 22nd of May and will complete the remainder of their finals Tuesday the 23rd and Tuesday the 24th.  
Finals Week Schedule  
Friday and Monday, May 19th and 22nd  – Senior Final Exams during periods 1 and 6 ONLY (regular bell schedule) 
Tuesday, May 23, 2022 (finals, grades 9-12)       Bell Schedule 
Period 0                                                                   7:20am – 8:23am 
Period 2                                                                   8:30am – 10:30am 
BRUNCH                                                               10:30am – 10:43am 
Period 4                                                                  10:50am – 12:50pm 
Period 7                                                                  12:57pm – 2:00pm 
Wednesday, May 24, 2022 (finals, grades 9-12)      Bell Schedule        
Period 0                                                                   7:20am – 8:23am 
Period 3                                                                   8:30am – 10:30am 
BRUNCH                                                               10:30am – 10:43am 
Period 5                                                                  10:50am – 12:50pm 
Period 7                                                                  12:57pm – 2:00pm 
Thursday, May 25, 2022 (finals, grades 9-11) Bell Schedule 
Period 0                                                                  7:20am – 8:23am 
Period 1                                                                  8:30am – 10:30am 
BRUNCH                                                              10:30am – 10:43am 
Period 6                                                                 10:50am – 12:50pm 
*Students in a 0 or 7th period, see your 0 or 7th period teacher for finals information.  
I want to thank you for supporting our school and most importantly for supporting your student.  Our students have proven their resiliency and accomplished a lot this school year. We have been confronted with historical challenges and our students and staff have continued to rise to the challenge.   
We will have a very robust summer school this year, from June 1-30, 2022.  This summer school will provide our students with an incredible opportunity with three periods of two-hour classes.  I hope that your student is able to take advantage of the opportunity this summer. Please speak to your counselor to explore possibilities for summer classes ASAP!   
Congratulations to the class of 2023, we are proud of you!  
It continues to be my greatest honor and privilege to be your principal for this school year!  Finish the year strong and have a great summer!   
Claws Up!  
Eric Cypher