However, as a post from the sometimes not so safe for work humor website Cracked.com points out, the geography does not work out.
The Austrian state of Salzburg does share a border with Italy but not Switzerland. In reality the family fled through Italy rather than Switzerland. While the foot crossing the Swiss Alps provided a beautiful ending to the movie, real-world complex political geography due to the collapse of the Austrian-Hungarian Empire allowed for the family's departure. According to the National Archives:
The von Trapps traveled to Italy, not Switzerland. Georg was born in Zadar (now in Croatia), which at that time was part of the Austro-Hungarian Empire. Zadar became part of Italy in 1920, and Georg was thus an Italian citizen, and his wife and children as well. The family had a contract with an American booking agent when they left Austria. They contacted the agent from Italy and requested fare to America.
Traveling with their musical conductor, Rev. Franz Wasner, and secretary, Martha Zochbauer, they went by train to Italy in June, later to London, and by September were on a ship to New York to begin a concert tour in PennsylvaniaThe movie not only changed the history and names of family members but the geography as well.