The listing below identifies the 25* Maryland high schools that send the most students to the Clark School.

In alphabetical order, the schools are:

• Aberdeen High School
• Archbishop Spalding High School
• Atholton High School
• Calvert Hall College High School
• Centennial High School
• Clarksburg High School
• Dematha High School
• Dulaney High School
• Eleanor Roosevelt High School
• Huntingtown High School
• Marriotts Ridge High School
• Montgomery Blair High School
• Mount Hebron High School
• North Point High School
• Northwest High School
• Poolesville High School
• Quince Orchard High School
• Richard Montgomery High School
• River Hill High School
• Severna Park Senior High School
• Sherwood High School
• Thomas S. Wootton High School
• Urbana High School
• Winston Churchill High School
• Walter Johnson High School

The Clark School's Top 25 Source Schools list was launched in 2009, and is now in its fourth year.