According to Ministry of the Environment statistics, Nagano (Chubu) has 193 onsen areas and 955 hot-spring sources. This page lists 104 onsen in Nagano with their water types. The most common water type among them is Chloride Spring (23 onsen).
Source: Ministry of the Environment, FY2024 Hot Spring Utilization Survey (as of March 31, 2025). Best-known onsen = most annual Wikipedia views.
| Water Type | Count | Share |
|---|---|---|
| Chloride Spring | 23 | 22% |
| Sulfur Spring | 23 | 22% |
| Simple Thermal Spring | 22 | 21% |
| Unknown | 16 | 15% |
| Bicarbonate Spring | 8 | 8% |
| Sulfate Spring | 5 | 5% |
| Carbon Dioxide Spring | 2 | 2% |
| Iron Spring | 2 | 2% |
| Other | 2 | 2% |
| Radium Spring | 1 | 1% |
| Facility | Water Type |
|---|---|
| Katakurakan | Unknown |
| Hakuba Happo Onsen | Simple Thermal Spring Alkaline simple spring |
| Azumino Shakunage no Yu | Simple Thermal Spring Simple spring |
| Tatsushima Onsen Seseragi no Yu | Unknown |
| Yurakukan | Unknown |
| Suzumushi-so | Unknown |
| Yu-furu Tanaka | Unknown |
| Nakano City Toyota Onsen Park Momiji-so | Unknown |
| Shibu Onsen Oyu The central communal bathhouse of Shibu Onsen's 'nine-bath pilgrimage,' a symbol of its outdoor-bathhouse culture. | Chloride Spring Sodium/calcium – sulfate/chloride spring |
| Shibu Onsen Ichiban-yu Hatsuyu Regarded as the first bath of the nine-bath pilgrimage, a communal bathhouse. | Chloride Spring Sodium/calcium – sulfate/chloride spring |
| Nozawa Onsen Oyu The central communal bathhouse of Nozawa Onsen's '13 outdoor baths' circuit, a symbol of the town with Edo-period architecture. | Sulfur Spring Simple sulfur spring |
| Nozawa Onsen Asagama-no-yu A communal bathhouse beside Asagama, the town's source-spring site known for its near-90°C water. | Sulfur Spring Sulfur-bearing sodium/calcium – sulfate spring |
| Name | What kind of onsen |
|---|---|
| Hakuba-Yari Onsen Details | At about 2,100m directly below Mt. Hakuba-Yarigatake in the Northern Alps, Japan's highest-elevation hot spring hut, reachable only on foot, with one of the largest natural spring flows in the country. |
| Honzawa Onsen Details | 'Unjo no Yu,' Japan's highest-elevation open-air bath at 2,150m, directly below Mt. Io in the Yatsugatake range. A 1–3 hour walk from the trailhead; past the forest-road gate no vehicle can enter, making it a true secluded hot spring. |
| Onsen Town | Summary |
|---|---|
| Kashio Onsen Geopark | One of the central geosites of the Southern Alps (Median Tectonic Line Area) Geopark, which sits almost directly above the Median Tectonic Line — the great fault that runs the length of the Japanese archipelago from Kyushu to Kanto. Despite lying deep in the mountains, far from the sea, Kashio Onsen's water is salty; it was once thought to be ancient seawater trapped underground, but is now known to originate from water carried up with magma. The Median Tectonic Line Museum in Oshika Village stands nearby. Details |
| Meiji Onsen Travelogue | A single inn with iron carbonate water in the mountains of Oku-Tateshina at the foot of Mt. Tateshina. Close to trailheads of the Yatsugatake range and known for its reddish-brown iron water, it is included in the Kanto/Koshin chapter of Tsuge Yoshiharu no Onsen. Details |
| Yashiki Onsen Travelogue | A single inn with weak saline water containing earthy chlorides, on the Sakae side of Akiyamago, a remote area on the Nagano–Niigata border. A cure retreat sending up steam quietly along the Nakatsu River gorge, it appears as 'Akiyamago' in the Kanto/Koshin chapter of Tsuge Yoshiharu no Onsen. Details |