Hello!
This time, we’ll be introducing the charms of Nagai Dam, located in Nagai City, Yamagata Prefecture.

Nagai Dam is one of Tohoku’s leading multipurpose dams, primarily used for flood control, agricultural irrigation, and power generation, but of course! It’s much more than that.

Not only is it a spectacular scenic spot that blends seamlessly with nature, it’s also a popular leisure destination with a wide variety of events, including lake activities and sightseeing experiences.

This is a must-visit spot for anyone looking to enjoy events, sightseeing, and activities in Yamagata Prefecture!

The dam is the tallest in Yamagata Prefecture! Basic information about Nagai Dam

Nagai Dam is a gravity concrete dam completed in 2011.

With a dam height of 125.5m, a crest length of 381.0m, and a total storage capacity of 51 million cubic meters, it is one of the largest dams in the Tohoku region.

It is said to be the tallest dam in Yamagata Prefecture in particular.

It plays an important role in the region, with a variety of functions including flood control, securing water for agriculture and daily life, and generating electricity.

In addition, Lake Nagai Hyakushu, which was formed as a dam lake, was named after the Kojiki, a historical text.

It is filled with the wish that “Japan will continue to be beautiful for a long time.”

How to visit Nagai Dam

You can freely tour the dam crest and spillway crest of Nagai Dam within the designated hours without making a reservation.
However, vehicles are prohibited from entering the dam, so tours can only be done on foot.

Additionally, tours with staff explanations can only be applied for by school-related social studies field trips or groups of 10 or more people.
Applications must be made at least two weeks before the planned tour date, so be sure to plan your application well in advance.
Nagai Dam Tour Application / Ministry of Land, Infrastructure, Transport and Tourism, Tohoku Regional Development Bureau, Mogami River Dam Integrated Management Office, Nagai Dam Management Branch 

Where is Nagai Dam? How to get there and enjoy it

Nagai Dam is located in Hirano Kitawakinosawa, Nagai City, Yamagata Prefecture, and is easily accessible, about a 15-minute drive from the city center. It’s the perfect place for a casual drive.

Right next to the dam is the Nagai Dam Administration Office, which has an observation deck in one corner. Here, there are panels displaying the dam’s structure, the history of its construction, and its relationship with the local community, which is well worth seeing.
Another great thing about the office is that you can get a dam card if you ask.

There is an observation point outside the administration building where you can get a panoramic view of the entire dam.
There is also a promenade along the top of the dam, allowing you to leisurely enjoy the scenery of the lake and mountains that spread out before you.

The attractions of Nagai Hyakushu Lake include activities

Nagai Hyakushu Lake, a reservoir created by the Nagai Dam, is a spectacular scenic spot that beautifully combines natural scenery with tourist attractions.

One of its great charms is that it shows completely different faces with each season, with the fresh greenery of spring, the cool water surface of summer, and the autumn leaves.

No matter how many times you visit, you’ll never get bored.

You can also enjoy a variety of seasonal activities at Lake Nagai Hyakushu.

For those who want to get some exercise, we recommend boat touring, pedaloes, and shower climbing.

For those who want to take it easy, you can enjoy the scenery at a leisurely pace on a sightseeing boat or amphibious bus.

Recommended Activities at Nagai Dam

The greatest appeal of Nagai Dam is its dynamic scenery that blends in with nature throughout the seasons, and the wide variety of activities that can only be experienced here.
Here we will introduce the activities you can enjoy at Nagai Dam.

Mibuchi Valley Boat Touring

The mysterious Mibuchi Valley, which can only be accessed by boat from Lake Hyakushu, is a scenic spot known only to those in the know.
As you walk along the route surrounded by towering cliffs on both sides, you’ll be transported to a place of silence and mystery, as if you’ve wandered into another world.

Season: Mid-May to early November (especially popular during autumn foliage season)
Duration: Approximately 40 minutes
Operation: Advance reservations required (regular and private tours available)
Features: Birdsong, the sound of water echoing through the valley, and a beautiful tunnel of autumn leaves

Experience the amphibious bus “ZABOOOON!!”

“ZABOOOON!!” is an amphibious bus that can travel on both land and lakes.
A regular bus that dives into the lake! It’s a very popular activity with families and children.

However, please note that the service will not be operating until fiscal year 2025.

Season: May through August
Duration: Approximately 40 minutes
Starting Point: Lake Hyakushu, in front of Noguchikan
Highlights: Ride on the lake while getting a close-up view of the dam’s edifice

SUP (Stand-Up Paddleboarding) & Water Activities

STAND-UP Paddleboarding (SUP) experiences on calm lakes and aquabiking are rapidly gaining popularity!
Guided tours are available, so even beginners can enjoy the experience with peace of mind.

Period: August to mid-October
Plan Options: SUP, pedalo, or paddleboat
Location: Shallow waters of Lake Hyakushu
Target Age: Elementary school students to adults (life jackets required)
Nagai Dam offers breathtaking views throughout the seasons.

Nagai Dam and Lake Hyakushuko reflect the seasonal changes of Yamagata Prefecture’s natural landscape like a painting.
The mountains and valleys surrounding the dam lake change their appearance with each season, offering new and moving experiences every time you visit.

For example, you can experience different beauty in each season: fresh greenery in spring, clear skies and the shining lake surface in summer, autumn leaves in autumn, and a silvery world shrouded in tranquility in winter.

It’s also a great spot for photography and nature observation, and you’re sure to discover something new every time you visit.

Recommended facilities and view spots around Nagai Dam

The area around Nagai Dam is dotted with observation facilities and experience spots where tourists can enjoy being in touch with nature.

• Nagai Hyakushu Lake Observation Point：Located next to the dam management branch office, it is a great observation spot with a panoramic view of the lake surface.
• Right and Left Bank Observation Plazas：They are popular photo spots where you can enjoy Lake Hyakushu from different perspectives.
• Ryujin Bridge：From the approximately 300m long bridge, you can enjoy a panoramic view of the mountains and lake.
• Tourist circular bus “Mawarun”：Access bus connecting roadside station “Kawa no Minato Nagai” and Nagai Dam (limited time operation)。

Why not combine a visit with Nagai Dam?

Summary

Nagai Dam is one of Yamagata Prefecture’s most popular tourist spots, boasting a beautiful blend of nature and tourism.
With its impressive dam scenery, breathtaking views that change with the seasons, and a wide range of activities and observation facilities, Nagai Dam is packed with attractions from every angle.

Perfect for family leisure, couples’ road trips, or solo travelers, Nagai Dam and its surrounding area are definitely part of your itinerary when planning your Yamagata sightseeing trip.

Unforgettable views and experiences are sure to await you.

Basic Information about Nagai Dam

• • • Address:Kusaoka, Nagai City, Yamagata Prefecture 993-0081
    • Parking:Available
    • Access:Approximately 15 minutes by car from the “Kawa no Minato Nagai” Roadside Station
    • Contact:Ministry of Land, Infrastructure, Transport and Tourism, Tohoku Regional Development Bureau, Nagai Dam Management Branch Office 　0238-88-5740