Opening of Yellowstone’s historic Mammoth Hot Springs Hotel delayed

Harsh winter, difficult conditions forced delays to wastewater treatment system construction
 Mammoth Hot Springs Hotel (
Mammoth Hot Springs Hotel ( (KGWN)
Published: Apr. 14, 2023 at 10:16 AM CDT
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CHEYENNE, Wyo. (Wyoming News Now) - Wyoming’s winter strikes again.

Yellowstone National Park’s Mammoth Hot Springs Hotel spring 2023 opening has been delayed until the wastewater treatment system in the area is completed and operational.

Due to the heavy winter and difficult construction conditions, the new system will not be operational by April 28 as originally planned. The park is working closely with contractors to complete the project as quickly as possible.

The hotel closed immediately after the 2022 historic June flood because of damage to the area’s wastewater system. The North and Northeast Entrances are open to all traffic with no restrictions. Both road corridors were repaired last fall following the flood.

Although the hotel will be closed to overnight guests temporarily, the hotel’s gift shop, coffee and beverage service, and lobby will open as scheduled on April 28. Overnight accommodations will reopen immediately after construction of the wastewater system is completed. The hotel dining room and Terrace Grill will be temporarily closed and regularly scheduled tours departing from Mammoth Hotel will not be available.

All other services in Mammoth Hot Springs include: the Albright Visitor Center, general store, post office, medical clinic, and gas station.

The opening of the Mammoth Campground will also be delayed until the wastewater system is operational. The campground closed immediately following the 2022 flood and remains closed because the campground lacks an outlet for wastewater.

All communities near Yellowstone are open year-round, with local businesses offering a wide range of overnight lodging and recreation opportunities. Options include: Gardiner, Montana; Silver Gate and Cooke City, Montana; Cody, Wyoming; Jackson Hole, Wyoming; and West Yellowstone, Montana.

In June 2022, unprecedented amounts of rainfall caused severe damage to the North Entrance Road between Mammoth Hot Springs and the park’s North Entrance in Gardiner, Montana. In addition, a sewer line adjacent to the road carrying wastewater from Mammoth Hot Springs to a sewage treatment plant in Gardiner was ruptured. Staff quickly rerouted the wastewater into percolation ponds used between the 1930s and 1960s, allowing for summer day-use visitation and limited services.

Currently, a new wastewater treatment system is being built to serve the Mammoth Hot Springs area; however, this temporary system is not ready to support full hotel operations. Due to an above-average snowpack and cold temperatures this winter, construction of the system has proceeded slower than expected.

The park has authorized Yellowstone National Park Lodges to open other visitor accommodations earlier than normal to offset inconveniences to displaced guests with existing reservations for the Mammoth Hotel. Guests with reservations at the Mammoth Hotel will be offered opportunities to rebook at other Yellowstone National Park Lodges properties in the park based on available space.

Yellowstone staff are working to make the wastewater system operational and ensure it can handle expected use. It’s important that the system is fully functional, safe, and meets required environmental standards prior to the park reopening the hotel in Mammoth Hot Springs.

All other Yellowstone National Park Lodges properties will open as scheduled.