[2] The county was named for James Robertson, an explorer, founder of Nashville, and a state senator, who was often called the "Father of Middle Tennessee."

This was part of the Miro District (also spelled Mero), named after the Spanish Governor Esteban Rodríguez Miró of what was then Louisiana on the west side of the Mississippi River.

James Robertson, the explorer for whom this county was named, was trying to create an alliance with Miró that would allow free movement on the Mississippi River (which Spain controlled) to settlers on the Cumberland frontier.

Although initially, most settlers did not hold slaves, by the 1820s planters began to cultivate tobacco, a commodity crop that was labor-intensive and depended on enslaved African Americans.

The planters bought slaves to work their plantations, as well as to care for the livestock they bred - thoroughbred horses and cattle.

By the time of the Civil War, African Americans comprised about one-quarter of the area's population, typical for Middle Tennessee, where tobacco and hemp were commodity crops.

Most of the residents were still involved in farm work, and tobacco was the primary commodity crop, but agricultural mechanization was reducing the need for laborers.

Many African Americans left rural Robertson County and other parts of Tennessee in the Great Migration to northern and midwestern cities for employment and social freedom.

US 31W forms the eastern border with Sumner County and runs through White House and Cross Plains.