The Ion District, Ion Innovation District, or Rice Innovation District, is a technology park and innovation district in Midtown Houston which was established as a joint initiative between Rice University and the City of Houston. It has also been called the South Main Innovation District. The district's central hub and first building is the Ion, which opened in 2021 after owner Rice Management Company (RMC) converted it from a former Sears store. The building houses coworking and office spaces, business incubators and accelerators, classrooms, a prototyping lab, investor studio, and restaurants. Current tenants include Chevron Technology Ventures and Microsoft. The district also includes Greentown Labs Houston, a business incubator focused on climate technology and sustainable energy, and a large outdoor plaza.

Midtown is a central neighborhood of Houston, located west-southwest of Downtown. Separated from Downtown by an elevated section of Interstate 45, Midtown is characterized by a continuation of Downtown's square grid street plan, anchored by Main Street and the METRORail Red Line. Midtown is bordered by Neartown (Montrose) to the west, the Museum District to the south, and Interstate 69 to the east. Midtown's 325 blocks cover 1.24 square miles (3.2 km2) and contained an estimated population of nearly 8,600 in 2015.