Newmarket High School is a secondary school located in Newmarket, Ontario, Canada. It is one of four high schools in Newmarket under the jurisdiction of the York Region District School Board and currently educates approximately 1400 students from Grades 9 to 12. The phoenix and the Viking are the school's symbols and the school's colours are purple and gold.

The school was founded in 1843 as a "grammar school", located on Raglan Street and Millard Avenue in Newmarket. As an institution, Newmarket High School is the fourth oldest high school in Ontario (oldest being Kingston Collegiate and Vocational Institute c. 1792 and Cornwall Collegiate and Vocational School c. 1806 and Jarvis Collegiate Institute c. 1807) and oldest in York Region. This original school, which could accommodate 46 students, was built at a cost of $75.

However, by the 1870s, Newmarket's growth had rendered the original school inadequate to the task of educating the town's youth. So, in 1876, at a cost of $6,000, a new building was constructed at the southeast corner of Pearson and Prospect Streets in Newmarket, where the school was located for most of its history.

On March 16, 1893, a temperamental wood-burning furnace put an end to this building and its additions when it set off a fire that burnt the school to the ground.

In 1894, a new building was built on the same site, incorporating the innovation of electricity. This building stood until March 31, 1928, when yet another fire, this one of mysterious origin, once again utterly reduced the school to ashes. The fires led to the adoption of the orange Phoenix bird as the school's official symbol.

The same year, yet another new school was built on the Pearson Street site by George Roper Gouinlock (son of George Wallace Gouinlock), this one hailed as “one of the most modernized educational institutions in the Dominion of Canada.” This building stood for decades and underwent many additions and renovations over the years, most notably a major addition consisting of a classroom block and an additional gymnasium in the late 1950s, and a new school library in the 1960s.

Despite the additions, however, the 1960s saw an increasingly intolerable situation developing at Newmarket District High School, as it was then known. The school was overcrowded to the extent that not only did students have to share lockers, but the school day was also run in two shifts to accommodate everyone. The situation was addressed in 1962, when Huron Heights Secondary School was opened, providing Newmarket with a second high school.

By the 1990s, however, it had become clear that the existing building could no longer cope with local population growth and its facilities were becoming increasingly outdated. Plans were made to move the school to yet another site. This move (to the school's current location) was completed in October 1996, with the previous building briefly housing Newmarket Public School before being torn down in 2000; the site is now occupied by a residential neighbourhood with a parkette.

A significant portion of NHS's graduating classes goes on to pursue post-secondary education at universities across Canada (mostly in Ontario). The most popular destinations include McMaster University, Wilfrid Laurier University, Carleton University, University of Western Ontario, and Brock University, University of Waterloo, University of Toronto, and Queen's University.

Current academic programs offered at Newmarket High School include a gifted/enriched program, Advanced Placement courses, and most recently, a French immersion program.

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• Education in Ontario
• List of secondary schools in Ontario
• York Region District School Board
• Newmarket, Ontario

• Newmarket High School's History

• Newmarket High School