The district formally began with the first graduating class of Mehlville Senior High School in 1930.
The district as we know it today first consisted of smaller, independent educational entities working under a feeder school system.
[2] In the 1950s and 60s, the state government of Missouri began to combine the thousands of small, rural schools into larger districts.
"[4] After a rapid increase in enrollment of elementary and secondary students as a result of the increase of the area's population, bus transportation was introduced in 1951, and the district was forced to construct more educational facilities to meet the growing enrollment.
In 1956, the district received the official title to 45 acres formerly part of the Veterans Administration Hospital Reservation at Jefferson Barracks; the land is now home to Beasley Elementary.
In the mid-to-late 1960s, the district continued to expand, constructing Trautwein and Wohlwend Elementary in 1964 and 1969, respectively.
It operates the following schools: All MSDR9 elementary schools teach kids from Kindergarten (5-6 y/o) to 5th Grade (10-11 y/o) Beasley was built in the 1960s on grounds that were originally part of the Veterans Administration Hospital at Jefferson Barracks, located in an unincorporated area near southeast Mehlville.
The modern Hagemann Elementary was built in 1994, but the foundations for the original school were laid as early as 1898.
Located in an unincorporated area near Concord, the school mascot is the Hawk, and its 375 students will eventually go on to Washington Middle.
The school mascot is the Lion Point dates back to 1840, when Mrs. Katherine Burg dedicated a room in her Oakville farmhouse as a classroom.
The district provides bus transportation from each of the other elementaries to MOSAIC after the busses drop off the students at the schools.
The middle schools also host Academy, a personalized learning program based on STEM/STEAM principles.
It is located in North Oakville on the same property that once was home to Bernard Elementary School.
The school is located in Mehlville, and is named after former teacher and administrator Margaret Buerkle.
It is the oldest middle school in the district and shares a campus with Trautwein Elementary.