This paper explores the post-9/11 2001 US security measures and the impact of evolving border security policy on the lives of the residents of the California–Baja California region a decade after the 9/11 terrorist attacks. It also considers the perceptions of the border people about this policy. It shows the results of qualitative fieldwork aimed at answering questions related to the main changes brought about at the border with the new policy initiatives, the effect of the creation of the US Department of Homeland Security (DHS) on the functioning and dynamics of the ports of entry, the most affected groups in the local community, their adaptation to the changing realities at the border and the border crossings, and the differences in border perceptions of the San Diego–Tijuana border region prior to 9/11 compared with the border today. The literature regarding terrorism, security and borders is reviewed, fieldwork results are presented and the findings are compared with those of the existing literature.