Land at this site was first designated for a courthouse in 1854, one year after the Territory of Minnesota created Blue Earth County. In 1856, the county built its first county building here, a log jail and frame single-story house for the sheriff. The next year, it constructed a stone building at Hickory and Fourth streets that became known as the first county courthouse. In 1867, a new two-story structure with a basement was built for the jail, sheriff's quarters, and the county's first official courthouse, the log jail and house were torn down, and the stone building was enlarged for officials, but the space soon proved inadequate. A resolution in 1877 recommended constructing a new building, but disagreement over whether it should be in Garden City or Mankato delayed action for several years. After the Mankato location was approved, the courthouse was completed on October 1, 1889. Designed by Healy and Allen of Minneapolis and built by contractors Ring and Tobin of Minneapolis, it combined French and Italian Renaissance styles and was constructed entirely of Minnesota stone from local quarries, with varied finishes including alternating smooth and rock-faced stone. The building is symmetrical on each side, with its original entrance and elaborate portico on the northwest side, and above that entrance rises a four-story tower with a copper dome, a statue of Lady Justice, and a clock added in 1991 through private donations. Originally built with two floors, a basement, and an attic, it underwent an extensive remodel beginning in 1965 that added another floor, created more space, and gave the interior a more modern look while preserving the historic exterior. In 2009, the court system moved to the new Blue Earth County Justice Center, and the county continued to house several departments in the historic courthouse. The building was added to the National Register of Historic Places in 1980 and was locally designated a Heritage Preservation Landmark in 2012.