The Evansville Post Office, also historically known as the U.S. Post Office, Customhouse, and Courthouse, is a premier architectural masterpiece of the High Victorian Gothic style, designed by the prominent Supervising Architect of the U.S. Treasury, Alfred B. Mullett. Constructed between 1875 and 1879, this monumental limestone edifice stands as a testament to the federal government's post-Civil War investment in the region's civic infrastructure. The building's exterior is characterized by its dramatic, steeply pitched rooflines, pointed arch windows, intricate stone carvings, and a commanding central tower, making it one of the most visually striking and architecturally significant 19th-century public buildings in Southern Indiana.

Beyond its architectural prominence, the building holds immense historical significance as a physical symbol of Evansville's late-19th-century economic golden age. Strategically positioned on the Ohio River, Evansville emerged as a bustling inland port of entry, and the establishment of a customhouse, federal court, and post office within this grand structure highlighted the city's critical role in national commerce, river trade, and regional judicial administration. By consolidating these vital federal services, the building served as the civic and economic anchor for the growing metropolis during a pivotal era of industrial expansion. Listed on the National Register of Historic Places in 1971, it remains a cherished monumental landmark of Evansville's historic downtown.