O. Henry Hall, Former federal courthouse and post office in Downtown Austin, Texas, United States.

O. Henry Hall, originally the U.S. Post Office and Federal Building, stands at Sixth Street in downtown Austin. Architect James G. Hill designed it, with Abner Cook partly supervising construction; the Renaissance Revival courthouse and post office was finished in 1879 for $200,000. The Texas State University System has used it as its administrative headquarters since purchasing it in 2015.

The building was completed in 1879 and initially served as a federal courthouse and post office for the city. In 1968 it was acquired by educational institutions and transitioned from public to academic use.

The building carries the name of writer William Sidney Porter, known as O. Henry, who faced trial there in 1898. This connection links literary history to the architecture and draws visitors interested in the region's cultural past.

O. Henry Hall stands at 601 Colorado Street, within the Sixth Street Historic District, a short walk from the Sixth Street entertainment strip. It is an active office for the Texas State University System, so visitors should plan to view the Renaissance Revival exterior from the sidewalk rather than expect interior tours.

The building was completed in 1879 at a cost of $200,000, designed by architect James G. Hill and built partly under the supervision of Abner Cook. The federal district court met here until 1936; in February 1898 William Sidney Porter, later known as O. Henry, was tried and convicted of embezzlement in this building.