Yellowstone National Park, which attracts more than 4.5 million visitors annually, faces a constant threat from litter that can damage its delicate hydrothermal systems. The park’s geothermal areas, including Old Faithful and Midway Geyser Basin, are especially vulnerable because debris can clog vents, alter runoff, and introduce harmful chemicals.
The USGS Geology Program recovered 5,000 rocks and sticks, 280 hats—ranging from a FIFA 2026 World Cup cap to a Roblox bucket hat—and over 18 dollars in coins in eight different currencies. Other common finds included 54 camera lens caps, 47 hair ties, 42 pencils, 36 sunglasses, 20 hotel key cards, and 17 baby pacifiers. The program emphasized that foreign objects can permanently alter the natural flow of geothermal features.
USGS warned that coins, especially when deliberately tossed into hot springs, can clog vents and damage bacterial and algal communities, with repairs taking months or years. The agency also highlighted that hot springs are not wishing wells, contrary to popular belief.
Rangers on the geothermal trails report that a sudden windstorm can blow lightweight items—such as hats and wrappers—into the vents, exacerbating the problem. The team has developed a protocol to secure loose items during windy conditions and to educate visitors on proper waste disposal.
After the 2026 season ends, hats that can be reused will be washed and donated to local organizations, while the remaining debris will be processed and a report released in December to assess the long‑term effects on the park’s hydrothermal features.