Mueller /ˈmɪlər/ is a 711-acre (288 ha) Planned Unit Development (PUD) in the northeast-central portion of the city of Austin, Texas, USA. The project is in the process of long-term development on the former site of the Robert Mueller Municipal Airport, which was closed in 1999 upon the opening of Austin-Bergstrom International Airport in southeast Austin, itself a civilian adaptation of Bergstrom Air Force Base after its closure in the early 1990s.