According to archaeological studies, the earliest structures on the site of Janpyk-Kala date back to the ancient period (4th century BCE–1st century CE). Unfortunately, these original constructions have not survived to the present day. The fortress walls visible today belong to the medieval era and were constructed between the 9th and 10th centuries CE. Within the fortress, archaeologists have uncovered residential and artisan zones, which have been dated to the 12th–14th centuries CE.

One of the most remarkable features of the site is the partially preserved walls of a medieval palace—or possibly a temple—adorned with decorative facades. These structures also incorporate the distinctive Khorezmian technique of embedding reed layers into the construction for reinforcement, a method still used as late as the 19th century (notably in the historic city of Khiva).

On the fortress grounds, there is a small, makeshift cemetery dating to the Soviet period, containing several modern graves. Among these, a few older, weathered graves could predate the Soviet era, possibly from the early 20th century. The tradition of burying people at the sites of ancient settlements is common in Khorezm and Karakalpakstan. Local residents often regard such locations as sacred, believing that burying their loved ones here brings great blessings, as these lands were once inhabited by many generations of their ancestors.

Beyond its human history, the site occasionally reveals evidence of a much older natural past. Scattered across Janpyk-Kala’s grounds are fragments of ceramics, unearthed by rain, as well as shells of gastropods and bivalve mollusks. These remnants serve as a poignant reminder that millions of years ago, this land was submerged beneath a vast sea. Surrounding the fortress are deposits of green-colored rock, hinting at an even earlier marine environment. These green hues are due to chlorite minerals, which likely formed in low-oxygen conditions within iron-rich marine sediments.