50 Dean Lane, Stony Brook NY 11790 Phone: (631) 730-4300  |  Fax: (631) 730-4309 IMPORTANT PHONE NUMBERS: Main Office- 730-4300 Attendance/Health Office - 730-4310 Nathalie C. Lilavois, Principal Janine Farinella, Assistant Principal

William Sidney Mount School is one of five elementary schools located in the Three Village School District in Stony Brook, NY.  Currently, we house grades kindergarten through sixth grade.

US Dept. of Education designates WS Mount as a Blue Ribbon School!!
Click here for more information.  Visit the Dept of Education website.
Click here to watch the video!


Please be sure to check the Calendar and the Parent Notices regularly for important updates throughout the school year.   

    * Notice to Parents regarding Physical Education classes
    * Letter to Parents regarding jewelry in PE classes