Hold onto your hat—literally! Yellowstone National Park rangers have a message for visitors: While the park’s geothermal wonders might take your breath away, don’t let them take your hat, too.

As of September 2025, crews have fished more than 10,000 items out of the park’s hot springs and mud pots, including over 300 hats, according to Smithsonian. Even the smallest bits of debris, such as peanut shells, can alter the delicate chemistry and temperature of these thermal features.

The lasting effect is a serious issue. During the 1880s, Yellowstone’s famous Morning Glory Pool shimmered a deep purple. Today, it’s orange and red, largely due to trash being tossed into the spring throughout the years.

With more than four million people visiting the park annually, park officials say most “lost” hats are simply victims of the wind. Next time you’re in

Yellowstone, enjoy the view, but hang onto that hat!