The American Rolling Mill Company moved to Middletown in 1900.  It spurred the growth of the city's industries and resulted in the rapid growth of Middletown's population between 1900 and 1930. During that period, the number of residents swelled from 9,215 to 29,992.
 

Workers inside ARMCO	East Side Plant of ARMCO, 1918

The Miami Valley was particularly well suited for the making of paper and Middletown was no exception.  Like Hamilton, its neighbor to the south, Middletown attracted a number of papermakers including: Sorg, Oglesby, Wrenn, Crystal, and Gardner and Harvey Paper.

Gardner and Harvey Company, organized in 1900	Oglesby Paper Company, incorporated 1852