Just about a three-and-a-half hour drive down I-45 from the No. 4 city on this list takes us to a swath of Texas where the sprawl grows like weeds. The outsized city of Houston is so sprawling that Grammy award winning indie darlings Arcade Fire even wrote a song about it [source: Elmostehi].
America's fourth largest city, Houston spans a massive 600 square miles (1,554 square kilometers). That's large enough to fit Philadelphia, Baltimore, Chicago and Detroit within city limits. Like many urban areas that sprung to life in the post-World War II era, including Dallas, Houston was developed because it could be developed: The land was dirt cheap and there was plenty of it. Thus, builders had little incentive to erect high rise, multifamily buildings and instead expanded outward [source: ICIC].
Today, the area surrounding Houston continues to grow. The metro-area population climbed 7.5 percent during the last decade to nearly 6 million residents. Yet for the more than 2.1 million folks within city limits, living arrangements remain wide open with a mere 3,502 residents per square mile. That's much more room than in similarly-populated cities like Chicago (11,841 residents per square mile) and Philadelphia (11,379 residents per square mile) [sources: ICIC, Shauk, City of Houston, U.S. Census Bureau]. City officials have voted to change development codes so that more multifamily housing can be built downtown.