Construction began in early June, 1888, and was completed in September, 1889. An addition was made on the east side of the building between June 1, 1910 and March 1, 1911. This addition went unrecorded in the newspapers of La Crosse and no drawings for this addition have been found. However, historic photographs show this addition under construction and are dated. A large addition was made on the north end of the original building between December 1, 1931 and April 21, 1933.
The original portion of the building was built on lots 3, 4, and 5, of Block 32 of the original plat of La Crosse. These lots were purchased by the United States in 1886, from Mrs. G.A. Hayden and George Farnum. The addition of 1931-33 is on lots 1 and 2 of Block 32 of the original plat of La Crosse. These lots were purchased from the Knights of Columbus Building Association. A large house owned by Charles Seymour occupied these two lots until the addition of 1931-33.
A small addition was added to the east side in 1911. On the ground floor it contained an enlarged office for the Post Master and additional space for sorting mail. The second floor contained an office for the new Postal Inspector at the southeast end, and added a room on the courtroom at the northeast end. In the 1910-11 period an elevator was installed on the interior south wall at the second bay east of the tower. This elevator had a wire mesh cage and serviced all three floors until taken out of service about 1960. A large addition was added to the north end of the building between 1931 and 1933, and the upper story of the original building was changed from a mansard roof with gabled dormers to a full third story. The interior was completely remodeled at this time including the removal of the postal boxes and the screen. An industrial type wooden floor consisting of 6" long 2" x 4" blocks set on end was installed at that time. This was an attempt to minimize floor wear caused by the heavy mail carts.
Among the early tenants of the building was the area offices for the Signal Service, an early branch of the United States Army that later became the National Weather Bureau. Measurements of the weather were made from the roof of the building and flags communicated the information to the townspeople and the river boats that passed La Crosse. Other offices included the United States Marine Hospital, the Internal Revenue Service, and the United States Customs, The United States Circuit and District Court was held on the second floor until 1931-33 when it moved into larger quarters.