Established when Dakota County was first platted as a county in the Territory of Nebraska on March 7, 1855, and then rezoned in January of 1856.
The first election of a county sheriff was held in 1856.
In 1867 Nebraska obtained statehood and the state Legislature established rules and regulations for the sheriffs in state statute. These rules and regulations clearly defined the duties and the powers granted to the elected sheriff. It also made the Sheriff as the official responsible for maintaining the county jail located in the county seat, Dakota City.
When the first sheriffs were in office there were several towns within the county including : Omadi, Logan, St. Johns, Blyburg, Franklin City, Verona, Randolph, Lodi, Emmett, Nacora, Goodwin, Pacific City, Corburn Junction, Staton, and Covington. Currently in Dakota County there are the towns of: Jackson, Homer, Hubbard, Emerson, South Sioux City, Dakota City, and the unincorporated village of Willis. The sheriff’s office provides law enforcement to all but Emerson and South Sioux City, which have their own police departments.

Tragedy struck the Dakota County Sheriff’s Office on May 7th, 1982, when Deputy Michael McManigal was killed in the line of duty. Deputy McManigal was the first known member in the history of the Dakota County Sheriff’s Office to die in the line of duty.