© 2014 American Journal of Preventive Medicine. Background: Planners have relied on the urban development boundary (UDB)/urban growth boundary (UGB) and central business district (CBD) to encourage contiguous urban development and conserve infrastructure. However, no studies have specifically examined the relationship between proximity to the UDB/UGB and CBD and walking behavior. Purpose: To examine the relationship between UDB and CBD distance and walking in a sample of recent Cuban immigrants, who report little choice in where they live after arrival to the U.S. Methods: Data were collected in 2008-2010 from 391 healthy, recent Cuban immigrants recruited and assessed within 90 days of arrival to the U.S. who resided throughout Miami-Dade County FL. Analyses in 2012-2013 examined the relationship between UDB and CBD distances for each participant's residential address and purposive walking, controlling for key sociodemographics. Follow-up analyses examined whether Walk Scores, a built-environment walkability metric based on distance to amenities such as stores and parks, mediated the relationship between purposive walking and each of UDB and CBD distance. Results: Each one-mile increase in distance from the UDB corresponded to an 11% increase in the number of minutes of purposive walking, whereas each one-mile increase from the CBD corresponded to a 5% decrease in the amount of purposive walking. Moreover, Walk Score mediated the relationship between walking and each of UDB and CBD distance. Conclusions: Given the lack of walking and walkable destinations observed in proximity to the UDB/UGB boundary, a sprawl repair approach could be implemented, which strategically introduces mixed-use zoning to encourage walking throughout the boundary's zone.