[11] After the filming of Twin Peaks, Mount Si High School completed the building of a new campus and demolished the old one, starting in 2015.

"[20] That bond passed and modular classrooms did help, but Superintendent Joel Aune still advocated for a new building, claiming that the high school, built in the 1950s, had a “cobbled-together appearance, atrocious traffic flow, and was not education-friendly.

"[20] The middle school was not as crowded, so administrators decided to use $3 million the district had set aside for infrastructure improvements to convert it into a freshman-only campus.

We wanted to make it much more personal and student-centered, so we invested heavily in tech and have created learning communities, where smaller groups of teachers and students work together collaboratively.” He said the school had a “unique design that was a wonderful fit for what we’re trying to do philosophically with the freshmen.” The program is now being emulated elsewhere in the district.

[20] From 2012 to 2013, Mount Si High School opened a freshmen-only campus to solve overcrowding, adding an estimated $750,000 annually to future SVSD budgets while utilizing current district buildings.

[21] The population of the Snoqualmie school has been increasing, leaping 14% in 2005 and 2006, and growing about 3% per year after from 2006 to 2016 due to families moving to technology hubs in Seattle, Bellevue, and Redmond.

[20] Mount Si High School has received several honors for overall and academic achievement: Research on Mount Si High School has been conducted by education scholars since the 1960s, including research on its "innovative uses of social media,"[43] Competition and state-validated student films,[44] the "identification of employability skills,"[45] and the identification of CTE employable skills within the student body,[46] the teaching of American history,[47] and the teaching of journalism.

[48] In 2008, Mount Si High School was involved in a controversy over a visit by Reverend Ken Hutcherson, who was invited to speak about his experience growing up with racism.

The Snoqualmie Police Department conducted the investigation with the help of Washington State Patrol's Missing and Exploited Children Task Force.

[60] In February 2020, an image resurfaced of Principal Belcher at the end of school year car show giving a shaka sign in front of a truck with multiple Confederate flags displayed.

[62] Belcher addressed the concerns through the Snoqualmie Valley Record, expressing in his response that he "[takes] this work to heart and will do all I can do to find equality and justice every day at Mount Si High School.