The old Customs Building at the Calexico Border Station has been listed on the National Register of Historic Places at the National Level of significance. It is important for its role in politics and government as a custom house. It is a location where U.S. policies for international political and economic relations have been directly implemented since 1933. Its role as an immigration station has also had direct influence on the Hispanic heritage of the region. The station is also recognized as a notable example of regional Spanish Colonial Revival architecture as interpreted by the Depression-era federal building program under which it was constructed.
Calexico's function as a border community on the United States side of the international boundary with Mexico dates to its founding in 1900, initially as a surveyor's camp in conjunction with the construction of the canal bringing water from the Colorado River to the Imperial Valley. The first U.S. Customs office in Calexico was established in 1902. A Mexican counterpart in Mexicali, across the border, followed in 1904. Border traffic, both goods and people, increased rapidly, and Calexico grew with it. By the early 1930s the Customs House had moved two times, and it was apparent that a new facility was needed.
The federal agency responsible for the construction of the old Customs Building at Calexico in 1932 was the Public Buildings Branch of the procurement Division of the U.S. Treasury department. Part of a massive federal construction program began under the Hoover administration and continued under Roosevelt's Public Works Administration, the Calexico facility was realized under the aegis of Acting Supervising Architect James A. Wetmore. Design credit probably belongs to the Superintendent of the Architectural Division at Treasury, Louis A. Simon. In keeping with the general practice of the federal building program, the Calexico customs house is characterized by a restrained use of local architectural tradition, executed, in so far was feasible, with local materials and craftsmen.
Plans for the building were announced in 1932. Following a delay caused by a threatened federal appropriations cut, local businessmen raised $40,000 for purchase of the land at First Street and Heffernan Avenue. Work began at the end of 1932, with a cornerstone dedication in April 1933, The building opened in November, 1933, amidst great public interest. Like its counterparts at Tecate (1933), San Ysidro (1933), and Naco (Arizona), the border station played an important role in the daily life of the community and the two nations it served. The old Customs Building at Calexico continued in its original function until 1974, when it was supplanted by a border station nearby. It retains a high degree of architectural character and integrity.