In the 19th century, the majority of pioneers who settled in and around Onarga came from New England where education was valued as a prized asset. These pioneers did not waiver from that belief when they began their new life in the middle of an unsettled grass prairie.
Several villages in the surrounding territory met in Onarga to discuss the type and location of an` educational institution that would serve the needs of the area’s young men and women. As a result of these meetings, Grand Prairie Seminary (GPS) was created as a not-for-profit organization that incorporated in Onarga during July of 1863. By October of that same year, classes started using space in the local Methodist Church. Three teachers comprised the faculty and tuition ranged from $2 to $12 per term, depending on the courses selected.
Soon after the term started, a temporary building was constructed on the church lot serving as a one room school. GPS quickly outgrew this space, so a building campaign was started in 1864 to expand school facilities. Local citizens of Onarga pledged $7,000 which forged the bonds of a relationship that remains strong to this day. With the completion of a new ten-room Recitation Hall, the student body grew to 136 with a faculty of eight.
By 1880 the student body had grown to just over 300, so it follows that feeding and housing this many students became a challenge for Onarga. The solution was the construction in 1888 of a three story brick dormitory for ladies only, but male students were permitted to take meals there as well. The building was so well constructed that it served as a dormitory for over 100 years.
In 1892, a new brick and stone two story auditorium was built to serve as a cultural center for the entire area. After a 1933 fire, the auditorium was rebuilt with a seating capacity of 435 that provided the community with a site for movies, plays, lectures and recitals.
In 1901, Grand Prairie Seminary became affiliated with Northwestern University as a preparatory seminary with each GPS diploma endorsed by Northwestern. Grand Prairie Seminary still enjoys a relationship with Northwestern University.
In 1907, a brick gymnasium was built which to this day houses a swimming pool, two full basketball courts and one of the few remaining suspended indoor running tracks.
The enrollment at GPS peaked in 1904 with 655 students. However, as nearby communities built their own accredited high schools, the number of students attending GPS dropped to a low of 55 during the 1916-17 school year.