The Dongguk Yeoji Seungnam, a Joseon-era geographic text, records cockles as a specialty product of Jeolla Province. Based on this record, it appears that the taste of cockles from this region, and Jeolla Province more broadly, had already become widely known long ago. Cockles were considered among the finest delicacies served at the royal table, and they were regarded as precious enough to be an essential offering at ancestral rites.
Interestingly, however, a significant share of the cockles harvested nationwide today comes not from Beolgyo itself but from the neighboring county of Goheung. Yet a considerable geographic accident is largely responsible for why "cockles" so readily bring Beolgyo to mind. Because anyone leaving the Goheung Peninsula must inevitably pass through Beolgyo, cockles caught in Goheung were gathered and distributed through Beolgyo, and the name "Beolgyo cockles" naturally took hold. This reputation was further cemented when Jo Jeong-rae's novel The Taebaek Mountains, set in Beolgyo, achieved widespread popularity. A place that served as a transit point for distribution, rather than the actual production site, ended up representing the name itself.