How do cities grow? And how do decisions made about mobility and territory impact and structure that growth? Focusing on Houston, Texas after the Second World War, this article looks at how decisions made by city officials helped cement the dual processes of annexation and highway building into the city's growth structure. These strategies, while helping to explain how Houston become a leading metropolitan center during the second half of the twentieth century, also turned into path dependencies that limited Houston's mobility choices and stretched the city's ability to provide services to its citizens. The implementation of these two growth mechanisms shaped the unique development of the city and structured its relationships to the communities around it.