International migration made the Spanish population grow by 10 percent between 1998 and 2008. This paper studies where migrants settled and how natives reacted to such a huge and rapid inflow, the largest and fastest migration-induced increase in the OECD. Our preliminary results show the existence of two types of neighborhoods in metro areas: (i) large cities where immigrants clearly displaced natives and (ii) smaller satellite towns (suburbs) into which both natives and immigrants located. The resulting average segregation levels in Spain mask vast differences across neighborhoods and immigrant nationalities. To estimate the geographical mobility in Spain, this paper uses micro-data from 2000 to 2009. In addition, we geo-codify all addresses so as to have a flexible and exogenous/geographic definition of neighborhood and we include a large set of controls, such as the geographic distance to the city or metro area center (geo-coded data) or the gravities to all amenities in Spain (e.g., hospitals, schools, and train stations).