Crystal Lake South High School

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Welcome Back

The first day of school is Wednesday, August 12, 2026.

Welcome Back

The first day of school is Wednesday, August 12, 2026.

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A group of female student posing at the color toss event.

Current Families

We partner with families to support their students’ educational journey, ensuring students enter with promise and leave with purpose.

Parent and Guardian Resources

A group of male student posing at the activities fair.

New Families

We foster belonging, strong relationships, and provide relevant, engaging coursework so every student feels known, supported, and challenged.

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Latest News

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July 22, 2026

Crystal Lake South Back-to-School Guide 2026-27

Back-to-School Guide Crystal Lake South High School Welcome, Gators! Welcome to the 2026–2027 school year! This guide will help you and your student start the year off right as we prepare to welcom...

July 9, 2026

Athletic Registration for School Year 26-27

Athletic Registration for the 26/27 School year is now open. Registration must be completed on the Arbiter Registration Website PRIOR to tryouts/practices. If you have not yet registered your stude...

Michelle Kidd holding Inaugural Memorial Award

May 11, 2026

Michelle Kidd Honored with Inaugural Chamber Award

Crystal Lake South teacher Michelle Kidd was honored by the Crystal Lake Chamber of Commerce with the Inaugural Robert & Rosemary Blazier Memorial Award on May 7.

Students holding award from culinary challenge

April 21, 2026

CLS Pair Places Second at MCC Culinary Challenge

Cullen Perri and Temire Onome-Ojigbo place second at McHenry County College High School Culinary Challenge, making four identical dishes in 90 minutes.

Students holding trophy from competition

April 20, 2026

CLS Math Team Students Earn Highest Finish in Program History

The CLS math team had 14 students represent the school at the state finals with two seniors finishing second in the oral competition

Healthcare professional speaking with students

April 17, 2026

D155 Holds First Healthcare Careers in Under Four Years Panel

Over 100 students across all four schools interested in health careers attended to listen to a panel of health professionals about their careers

Lily Floeter working with a student musician

April 13, 2026

Cary-Grove Hosts Chamber Music Event for D155 Musicians

Cary-Grove hosted musicians across all D155 schools for a chamber music event with guest group Ravenswood Winds, led by 2005 Cary-Grove graduate Lily Floeter.

March 25, 2026

CLS ACES Team Places Third at State Finals

The CLS ACES team finished in third place at the ACES state competition, their best since 2001

CLS at a Glance

2024-2025 Annual Report (English)

Informe Anual 2024-2025 (Español)

School Information

93%

Graduation Rate

#1

District in McHenry County

225+

Courses Offered

37

Dual Credit Offerings

$1.8

Scholarships Earned by Class of 2026

#1

Best Teachers in McHenry County

81%

Teachers w/ Master's Degree or Higher

200+

Sports & Extracurricular Activities Offered

Homepage

Welcome Back

Welcome Back

Upcoming Events

Latest News

Crystal Lake South Back-to-School Guide 2026-27

Athletic Registration for School Year 26-27

Michelle Kidd Honored with Inaugural Chamber Award

CLS Pair Places Second at MCC Culinary Challenge

CLS Math Team Students Earn Highest Finish in Program History

D155 Holds First Healthcare Careers in Under Four Years Panel

Cary-Grove Hosts Chamber Music Event for D155 Musicians

CLS ACES Team Places Third at State Finals

93%

#1

225+

37

$1.8

#1

81%

200+