Early growth in the region was centered on Lawrenceburg which became an important railroad junction connecting two of the regions major rail lines. A contention existed between the towns of Lawrenceburg and the mostly German-speaking immigrants that dominated Rising Sun over the favored status of Lawrenceburg as the county seat. The rivalry between the two towns was resolved in 1844 when the Indiana State legislature separated the portion of Dearborn County south of Laughery Creek and created the last and smallest Indiana county, county of Ohio on March 1, 1844, with Rising Sun designated as its county seat.