The exterior of the cathedral, with two lofty towers flanking the faade, is rigorously formulated in the style transitional between baroque and neoclassicism.
The Treasury Department favored neoclassicism as the appropriate architectural style for most of the federal buildings constructed during this time period.
During its height, it was eminently baroque, concluding with a short rococo period leading to an incipient neoclassicism until the transition to the republican period.