Mt Haruna

Mt Haruna (Japanese: 榛名山) is a complex caldera system. It's a broad ancient volcano whose outer rim is lined with multiple peaks, while its center holds Haruna Lake and the elegant lava dome of Haruna‑Fuji (榛名富士). The highest point of the massif is Mt Kamon (掃部ヶ岳), a forested outer‑rim peak with long, gentle ridges and wide views across central Gunma. Haruna‑Fuji, by contrast, rises sharply from the lakeshore as a near‑perfect cone.

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I enjoyed the circuit hike linking Mt Kamon and Haruna‑Fuji, which captured the full variety of this volcanic landscape. I started near Lake Haruna, where steep trails climb steadily toward the outer rim. The ascent to Mt Kamon is moderate, weaving through quiet woodland before emerging onto a rounded summit with views toward Mt Akagi (赤城山) to the east. The ridge here is gentle and atmospheric, shaped by the caldera’s ancient uplift rather than sharp volcanic cliffs.

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From Kamon, the circuit descends toward the caldera floor, crossing meadows and passing viewpoints above Haruna Lake before reaching the base of Haruna‑Fuji. This peak is short and steep, a lava dome whose slopes are covered in mixed forest and summer flowers. The summit is small and offers a clear view of the lake directly below and the ring of outer‑rim mountains surrounding it. Haruna‑Fuji can also be reached by ropeway. Completing the loop brings hikers back along lakeside paths, passing marshland, flower fields, and viewpoints that reveal the caldera’s full shape.

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(All information here is based on personal observations and experiences. Check official sources before planning or starting any hikes.)