Located in a beautiful river valley, Mankato is known as the "Bend of the River" town, where the mighty Minnesota River changes course. The first settlers came to the Mankato area in 1852. They brought many things with them including some musical instruments and their voices. Singing societies and choirs were soon organized and in 1862 a band was formed. As the singing groups began singing more challenging compositions, the instrumental accompaniment of an orchestra was often needed. Throughout the years, many temporary orchestras were formed for specific events, using "pit" musicians (from the early days of no sound movies), and other local musicians.

In 1890, May Griffin came to Mankato from Boston to teach at the Normal School (now Minnesota State University, Mankato.) She would often organize choirs, choruses and glee clubs and then would combine them to perform operas and oratorios, for which she would need instrumentalists for an orchestra. In 1922, she organized 150 voices, 4 soloists and a full orchestra to perform Handel's "Messiah." They performed in front of an audience of 1700 people and it was the biggest musical event that had ever happened in Mankato. The local newspaper said that Mankato was the musical capitol of the state. It was from this performance that the idea of having a permanent orchestra in Mankato can be traced, although it would be nearly thirty years before it actually happened.

The Mankato Symphony Orchestra was organized in 1950 by the local Musicians Union, the State Teacher's College, Gustavus Adolphus College and the Mankato Public Schools. The organization became a nonprofit corporation the following May, 1951.