After its founding in 1836, Mexico was named county seat of the newly formed Audrain County. Growth in the primarily agricultural region was slow until the coming of the North Missouri Railroad and the Graduation Act that made land available from the federal government for 12.5[ an acre. With the introduction of breeding and training saddle horses, the discovery of fire clay deposits, and the implementation of more efficient means of turning the clay into heat resistant brick, Mexico's star ascended. During its heyday, the city was known as the "saddle horse capital" and the "firebrick capital of the world." Today Mexico continues to survive and thrive as "main street of the Midwest."