In 1874 Missouri mandated that schools needed to be established within a one hour walking distance or two miles from the students in the area. This can also be referred to as the "child-walking distance per hour" measure and it resulted in around 10,000 school districts in Missouri, most of them rural. This change also resulted in collecting taxes from the township to finance schools, compared to the private school system that was in use before. In the 20th century, there was a gradual reduction in the number of one-teacher schools. The disappearance of these schools can be shown with the following statistics: 1917, 9,000 schools; 1930, 7,352 schools; 1948, 5,125 schools; 1953, 4,000 schools; 1955, 2,500 schools; 1959, 1,028 schools. 

The 1911 Atlas of Nodaway County (on the left) displays the organization of rural school districts in the county. The districts were numbered starting in the northeast corner of the county with number 1 and proceeding left continuing consecutively to the south edge of the county. There were a total 181 districts in Nodaway County, but over time many of these districts were consolidated and by 1931, the number of districts was reduced to 132. Of these, 113 were rural schools, while the remaining nineteen were either city or consolidated districts. Many children went from going to a smaller district school, to then have it consolidated, and end up at a larger school in the county, such as students who started out at Union School in 1899 and then graduate from Elmo High School in 1908.