50 Dean Lane, Stony Brook NY 11790
Phone: (631) 730-4300  |  Fax: (631) 730-4309

Attendance/Health Office: 730-4310
Transportation Office: 730-5070, Fax: 730-5095
Weather Related Closing Information: 730-4050

Kathryn White, Principal
Merrilleen Heidrich, Assistant Principal

School Hours: 9:25 a.m.-3:40 p.m.

School Drop-Off/Pick-Up Procedure

Building Security Information


 Hip Pickles Come to Mount to kick off the 2015 - 2016 School Year! 

Thank you to the Mount PTA for this fun event that taught students about treating others the way they would like to be treated in a fun and interactive way!




Article: Keeping Kids Cool at School 


2015-2016 Supply Lists 

(Now located on side navigation)





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.   



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Tuesday, October 13, 2015   |  District Home