Old United States Post Office and Courthouse, Historic federal building in Miami, United States

The Old United States Post Office and Courthouse is a three-story masonry building at 100-118 Northeast 1st Avenue in Miami, designed by Kiehnel and Elliott with Oscar Wenderoth and built 1912-14. Its pale tan facade has round-arched openings on the ground floor and rectangular windows above, divided by pilasters, with a projecting cornice below a dark tiled hipped roof. A plain square tower rises at the left rear, and the corner inscription reads "UNITED STATES POST OFFICE AND COURT HOUSE".

Construction took place over a few years in the 1910s, making this one of the first major federal buildings in the young city of Miami. The post office and court later moved out, and in 1937 the structure was sold to the First Federal Savings and Loan Association of Miami.

The building's name changed with its uses: it opened as a federal post office and courthouse, stood abandoned by the early 1930s, and in May 1937 was bought by Dr. William Homer Walker for his First Federal Savings and Loan Association of Miami. The bank stayed until 1973, when it moved to the thirty-two-story First Federal Building at One Southeast 3rd Avenue.

The building stands at 100-118 Northeast 1st Avenue, at the corner where the "NE 1 AVE" and "ONE WAY" signs hang in front of the facade. The photographs show only the exterior, so the arched ground-floor openings, the iron balconies and the square tower at the left rear are what a passer-by can see from the street. The sources record no public interior access.

For about fifteen years, the building's third floor held the Miami Weather Bureau, where hurricane warnings were sent out. From the roof, instruments measured the sky, and this site was the origin of storm alerts during severe weather in 1926 and 1928.