In 1882, the first school was established in St. Thomas. This school was a small timber structure, and it was replaced by a two-story brick school with a large bell in the 1890s. This brick school was three blocks south and one-half block east of the current school building; St. Thomas’s first senior class graduated in 1899. The two-story brick school burned down in 1922, and a new school building, the current school, was built and began holding classes in 1923. This new school had an enrollment of 140 students and a faculty of seven.

Enrollment at St. Thomas increased steadily, and four local rural districts were annexed into the St. Thomas School District. In 1957, an elementary addition was added to the original school building that consisted of six classrooms with extensive remodeling to the existing building that included a hot lunch kitchen and dining facilities. Along with this project was the construction of a new large auditorium and multi-purpose room. The enrollment, after the completion of the new school building, consisted of 290 students and 14 faculty members. In 1959, St. Thomas School had its highest enrollment of 325 students and a faculty of 16. In the summer of 1968, construction began on the south end of the original school building a new lobby to the gymnasium, home economics facilities, science room and library were added to the school. The school’s largest graduation class was in 1968 with 31 graduates.

St. Thomas School continued to have steady enrollment into the 1970s. By 1990, the graduating class had dropped to eight students, but enrollment went back up, with the highest graduating class in recent years with 20 students in 1997. In 2014, St. Thomas School started a Pre-School program with three students that brought the total enrollment to 95 students, and graduated 10 that spring. The Class of 2021 will be the last class to graduate, graduating three. Thirty-four students were enrolled in K-12, with a faculty and staff of 16.

In the 2018-19 school year, the St. Thomas School Board decided to look at options for consolidating. The decision was made to consolidate with Grafton School District #3. Both towns had a vote in the summer of 2020, with both approving the consolidation by the end of the 2020-2021 school year, thus creating the new Grafton School District #18.

*All information from the History of St. Thomas School was found in the 1975 All-Class Reunion Booklet and 1980 St. Thomas Centennial.