In the early 21st century, food security has become an urgent public concern, arguably more entangled with social, political and environmental problems at multiple scales now than in the past. This paper examines approaches to food system change emphasizing regionalization, rather than either localization or globalization, to consider framings of food security. An enlarged food security risk frame--one that starts with food safety crises and the threat of agrifood terrorism but also recognizes new, more diffuse threats to food availability likely with global environmental change, provides common ground now for diverse institutional interest in regional food systems models. Combining discursive approaches to food security with territorial and relational conceptualizations of the region and regionalization, the paper develops a comparative analysis of three emerging regionalization initiatives in the United States: 1) work by the Northeast Sustainable Agriculture Working Group (a civil society organization); 2) the U.S. Department of Agriculture's Know Your Farmer, Know Your Food initiative; and 3) the Walmart Corporation's Heritage Agriculture initiative. It finds that institutions with markedly different histories, interests and power can align with a widening, ascendant food security risk frame. However, their approaches to regionalization reflect varying combinations of territorial and relational priorities, and suggest uneven implications for other food security concerns, such as community and food access.