In this article I examine how the US–Mexico border is framed within the CaliBaja Bi-National Megaregion, a cross-border initiative promoting the region as a competitive hub for business and innovation. The study, which draws on the concept of spatial imaginaries, highlights how regional boosters selectively construct and mobilize narratives that portray CaliBaja as a seamless, borderless megaregion with complementary resources across San Diego, Imperial County, and Baja California. Through analysis of promotional materials, planning documents, and interviews, I demonstrate that the border is discursively valorized as an economic resource—emphasizing labor-cost differentials, industrial complementarities, and gateway functions—while its constraining or contentious aspects, including militarized ports of entry, social inequalities, and precarious labor regimes, are largely obscured. The CaliBaja case illustrates the normative and selective nature of the megaregional imaginary: it aggregates desirable elements to create an idealized, globally competitive vision while marginalizing realities that complicate the narrative. Finally, the study situates CaliBaja within broader historical and regional trajectories, showing how cross-border imaginaries are negotiated amid competing visions, persistent inequalities, and securitization pressures to offer insights into the discursive construction of borderlands as spaces of opportunity and exclusion.