At a time when Hispanics are establishing a distinct social and cultural space in the United States, the geographical borders between Mexico and the USA, although highly secured, tend to become blurred. The linguistic and political intricacies of the Latino experience are therefore raising the delicate issue of the legitimate occupation of the land. This claim to space is particularly flagrant when one considers the high proportion of Spanish place names in the American Southwest, although it may be argued that this nomenclature was inherited from the era of colonization. The reasons why individuals, and beyond them nations, bestow names upon geographical features and human settlements respond to a series of personal, cultural, religious, political, and aesthetic values to which these populations are receptive. Clearly enough, in their exploration of the New World, Spanish explorers and colonists have baptized a few places Santa Fe, Corpus Christi, and San Francisco, which obviously testify to a missionary past. This legacy is of primordial significance as it precisely echoes the oft-quoted principle - among contemporary Hispanics - that Mexicans did not emigrate to the Southwest, but have moved north from Mexico. One may thus assume that the presence of a Latino population has encouraged the high persistence of Spanish place names in the Southwest. Yet, as the region passed under American control in the mid-nineteenth century, the demographic change from Spanish speakers to Anglos has had an effect on the toponymy: claiming this space their own, English namers quite predictably privileged their own culture and history. Given these relations to space and national identity, we can wonder how the Spanish nomenclature maintained itself, even accepting new developments passed the nineteenth century. The contemporary adoption - by non-Latino residents - of Spanish names (such as La Bodega, Plaza Nacional, Marina Del Rey) for their stores, streets, and neighborhoods shows that this toponymic mestizaje is bringing more to the land than a few exotic names. Beyond semantics, the particularity of Spanish place names might well inscribe on Southwestern maps a cultural distinctiveness as well as a regional specificity. As the Spanish naming process has moved from colonial to mainstream, the legacy of the nomenclature underlines how fluctuating the ties between places and populations may be. If arrivals and departures determine borderlines, the Spanish namescape is then one constantly being crossed over.