The Indian Removal Act of 1830 forced the American Indian from southwest Missouri and opened the area for permanent settlers. The first settler in what was to become Lawrence County, John Williams, arrived in 1831 and established a home near what would later be the county seat, Mt. Vernon. By 1845, settlers had arrived in such numbers that a new county was formed from parts of Dade County and Barry County. It was named Lawrence County in honor of Capt. James Lawrence, killed in the War of 1812 after ordering "Don't give up the ship!"

The first sheriff of Lawrence County, Washington Smith, was appointed by the State legislature. A native of Virginia, Smith had brought his slaves with him to Missouri, as had the John Williams family and many others. All the early sheriffs, until well after the Civil War, were of southern birth and the War caused tremendous upheaval, not only in the sheriff's office but throughout the entire county. Many pro-Confederate settlers were forced to flee Missouri after the Northern victory in the Battle of Pea Ridge, AR, and Federal forces moved into Lawrence County to enforce martial law. A provost marshal's office was established in Mt. Vernon by the 15th Mo. Cavalry, commanded by former Sheriff John D. Allen, and much of the law enforcement was performed by Federal troops until the war ended in 1865.

Prisoners were held in a variety of facilities, beginning with a log jail built in 1846, the county's second year. Though wooden, the specifications called for a quite solid building. Two walls of 10 inch hewn logs were separated by a space of six inches. Between the two horizontal log walls, six inch vertical logs were inserted into the space. The log floor and ceiling were covered by one inch thick oak planks nailed down, with nails one inch apart, all over the floor. The only access was through a trap door in the ceiling, when a ladder was let down from above. Solid though it was, it was burned down seven years later by a prisoner who nearly perished in the fire.

A new jail was built in 1868 just off the Mt. Vernon square. Again, double-thick walls were used, though this time made of brick. It quickly proved to be inadequate and a third, two-story limestone jail was completed in 1874. It was the site of the three official hangings in Lawrence County, all conducted by the sheriff. The first was performed in full view of an estimated 5,000 spectators in 1877. A posse of 100 men formed a barrier around the scaffold after an attempt to "rescue" the condemned man was rumored. The two subsequent executions were performed outside a second floor side door, behind tall stockade walls erected for each occasion. Two men were executed for murder; one for rape.

The present jail was completed in 1986 and is of modern design, with greater security for both inmates and staff.