Okutama Town is Tokyo's westernmost municipality, located in the mountainous Okutama district approximately 90 kilometers from central Tokyo. This rural town in the Chichibu-Tama-Kai National Park has served as Tokyo's primary water source since the completion of the Ogochi Dam in 1957, which created Lake Okutama, one of the region's largest reservoirs. The town encompasses 225 square kilometers of forested terrain, with over 95 percent of its land covered by mountains and forests, making it Tokyo's least populated municipality with around 5,000 residents.
The area's significance lies in its role as Tokyo's green lung and water supply, while also preserving traditional mountain village culture. The Nippara Limestone Caves, formed over millions of years, extend approximately 800 meters into the mountainside and remain one of the Kanto region's most impressive natural cave systems. The town is crossed by the Tama River, which has been central to the area's logging industry history and now provides popular rafting and kayaking routes during warmer months.
Visitors come to Okutama primarily for hiking, with trails ranging from easy riverside walks to challenging mountain ascents. Mount Mitake (929 meters) and Mount Odake (1,266 meters) are popular peaks accessible via well-maintained trails. The Okutama Lake area offers walking paths and scenic viewpoints, while the Hatonosu Gorge provides dramatic valley views along a suspension bridge pathway. The town also features several onsen facilities where visitors can experience natural hot spring baths after outdoor activities.
Transportation to Okutama requires taking the JR Ome Line from central Tokyo stations like Shinjuku, with the journey taking approximately two hours to Okutama Station, the line's terminus. The town itself has limited public transportation, with buses connecting major sites but operating infrequently, making a private vehicle advantageous for exploring multiple locations. Most trails and natural sites are free to access, though the Nippara Limestone Caves charge an admission fee of ¥800 for adults.