The failure of the Mexican government to agree to a joint park along the border with the United States has been portrayed as a lack of consciousness about conservation within Mexico. Yet in the 1930s the Mexican government created and administered forty national parks elsewhere in the country. The absence of a joint border park gives cause to examine the larger historical context to compare interpretations of national parks and reasons for their incompatibility. Detailed correspondence and discussions of the failed border park project reveal the agenda of Mexican officials and the ways in which they differed from and argued with their counterparts in the United States. This article argues that the international park failures had less to do with Mexican incompetence or insufficient funds and more to do with Mexican opinions on the environment and on their perceived purposes of nature protection. Among other factors, the Mexican style of conservation valued central landscapes, easy access, and forest restoration over remote wilderness. Culturally distinct definitions of conservation and different interpretations of national parks precluded the creation of an international border park, despite years of negotiation.