Mt. Akagi — Caldera Lakes and Panoramic Views in Gunma

Trail Overview

Mt. Akagi (赤城山, Akagi-yama) is a composite volcano in central Gunma Prefecture, with its highest peak Mt. Kurobi (黒檜山, 1,828m) designated as one of Japan’s Hyakumeizan (100 Famous Mountains). The summit area features the caldera lakes Onuma and Konuma, creating beautiful scenery in every season.

As one of Gunma’s Three Famous Mountains (Jomo Sanzan), along with Mt. Haruna and Mt. Myogi, Mt. Akagi is beloved by locals and visitors alike. The compact loop course from Mt. Kurobi to Mt. Komaga-take provides a rewarding mountain experience in a relatively short time.

Recommended Route: Mt. Kurobi to Mt. Komaga-take Loop

This route climbs directly from the Onuma lakeside to Mt. Kurobi, then traverses the ridge to Mt. Komaga-take before descending back to the lake.

Course Time

Section	Duration
Mt. Kurobi Trailhead → Neko-iwa	About 30 min
Neko-iwa → Mt. Kurobi Summit	About 40 min
Mt. Kurobi Summit → Viewpoint	About 5 min
Viewpoint → Mt. Komaga-take	About 40 min
Mt. Komaga-take → Mt. Komaga-take Trailhead	About 35 min
Mt. Komaga-take Trailhead → Mt. Kurobi Trailhead (road)	About 20 min
Total (loop)	About 3.5 hours

Tip: From Mt. Kurobi summit, walk 2 minutes north to the viewpoint. On clear days, you can see the Tanigawa Range, Mt. Nikko-Shirane, and even Mt. Fuji — do not miss this spot.

Access Information

• Nearest Station: JR Ryomo Line, Maebashi Station
• From Tokyo: Take the JR Ueno-Tokyo Line or Takasaki Line to Takasaki Station (about 2 hours), then transfer to the Ryomo Line for Maebashi Station
• Bus: Kan-etsu Kotsu bus from Maebashi Station to Akagi-san Visitor Center (about 70 min)
• By Car: About 60 min from Akagi IC on the Kan-etsu Expressway. Free parking at Onoko Parking Lot (about 100 spaces)

Convenience Stores, Shops & Restrooms

Convenience Stores (within 5 min of trailhead)

• Lawson near Maebashi Station North Exit: 2-minute walk from the station. Stock up before boarding the bus
• There are no convenience stores near Lake Onuma

Shops & Teahouses

• Akagi-san Visitor Center: Located by Lake Onuma with light meals and beverages
• Onoko area shops: Several restaurants and souvenir shops along the lakefront

Restrooms

• Akagi Hiroba: Public restrooms by Lake Onuma
• Onoko Parking Lot: Public restrooms available
• No restrooms along the mountain trail

Highlights

Spring (May–June)

• Massive azalea (rengetsutsutji) colonies bloom across the mountain (early June peak)
• Fresh green scenery around the caldera lakes

Summer (July–August)

• Cool temperatures at altitude — perfect for escaping the summer heat
• Boat rides available on Lake Onuma

Autumn (October)

• Beech and maple foliage paints Mt. Kurobi’s slopes in red and gold
• Reflections of autumn colors on Lake Onuma create a painterly scene

Winter (January–March)

• Snow-covered peaks and frozen Lake Onuma create a dramatic landscape
• Smelt ice fishing on Lake Onuma is a beloved winter tradition (late January–early March)

Packing Checklist

• ✅ Hiking boots (the Mt. Kurobi trail has steep sections)
• ✅ Rain jacket and pants
• ✅ Lunch and trail snacks
• ✅ Water (at least 1L)
• ✅ Warm layer (the summit can be windy)
• ⬜ Crampons and trekking poles (essential in winter)
• ⬜ Gloves and warm hat (winter)