Mo. Rev. Stat. § 167.121
If the residence of a pupil is so located that attendance in the district of residence constitutes an unusual or unreasonable transportation hardship because of natural barriers, travel time, or distance, the commissioner of education or his designee may assign the pupil to another district. Subject to the provisions of this section, all existing assignments shall be reviewed prior to July 1, 1984, and from time to time thereafter, and may be continued or rescinded. The board of education of the district in which the pupil lives shall pay the tuition of the pupil assigned. The tuition shall not exceed the pro rata cost of instruction.
(L. 1963 p. 200 § 8-12, A.L. 1973 H.B. 158, A.L. 1979 H.B. 280, A.L. 1983 H.B. 815, A.L. 2007 S.B. 64, A.L. 2018 S.B. 603, et al.)
(Source: RSMo 1959 § 161.093)
*This section was amended by both H.B. 1606 and S.B. 603, et al., 2018. Due to a delayed effective date, both versions are printed.