The boundaries of Heian-kyō were smaller than those of modern Kyoto, with at the northern limit corresponding to present-day , between and , Kyūjō-ōji in the south corresponding to slightly to the south of the present-day JR Kyoto Station and Higashi-kyogoku-oji in the east corresponding to present-day Teramachi Street (Teramachi-dōri).
The layout of Heian-kyō was plotted in accordance with the principles of geomancy as a square city.