The Mankato Post Office first opened in 1853 in a small building located on Front Street across the street from the Old First National Bank. The post office moved a number of times in the following years, quickly outgrowing each new location. In 1891 the search started looking for yet another location to house Mankato’s post office.
On April 1, 1896 the post office moved into its current location on Second and Jackson Streets. This new building housed 3400 square feet and had two towers, including a clock tower. Soon after opening, incandescent lights were installed in the clock and it was lit daily between 6:30 p.m. and 3 a.m.
In 1932, the post office underwent renovations. The two towers were removed and Vetter Stone was used to create a seamless addition that almost doubled the square footage.
In 1966, an expansion of an additional 6000 square feet was added to the rear of the building, completing the look of the post office as we know it today.
On June 17, 1980 the Mankato Post Office building was added to the National Register of Historic Places.