The courthouse was designed to provide suitable accommodations for important government offices and to demonstrate the commitment of the United States to the Island of Puerto Rico.

From the initial settlement of San Juan, this harbor side site has been critical to the city's defense and economic development.

Initially, portions of the site contained a Spanish fortification, the Bastion de San Justo del Muelle, which was built in 1639 (shortly after the city was invaded by the Dutch) and remained in place until 1897.

The first building of the complex was designed between 1906 and 1908 by the Office of the Supervising Architect of the Department of the Treasury, led by James Knox Taylor.

Congress authorized the expansion the same year, and plans were completed by the Department of the Treasury's Public Buildings Branch under Supervising Architect Louis A. Simon in 1938.

The north elevation features a centrally placed, projecting, multi-curved parapet and flanking entry portals.

Classically inspired pilasters divide the openings and are skillfully combined with wrought-iron balusters that are located on the second level.

Two towers capped with handsome, four-ton, bronze lanterns, flank the building and extend above the six-story main edifice.

[2] In 1996 the U.S. General Services Administration (GSA) commenced a meticulous restoration following the recovery of approximately 16,000 artifacts that were discovered during preliminary archaeological work on the site.

[2] In March 2000 the Society for History in the Federal Government awarded the John Wesley Powell Prize for Excellence in Historic Preservation to GSA for the rehabilitation and restoration work conducted at the building.