Wyoming Yellowstone reveals what visitors have left behind over the years

A surprising cleanup is underway

Imagine losing a hat, phone accessory or favorite souvenir at Yellowstone. Those small mishaps can become part of the park’s annual cleanup, and 2026 has produced a huge cleanup tally.

As of early September, the Geology team had removed more than 20,100 pieces of trash, 5,600 rocks and sticks, and over 280 hats from hydrothermal areas throughout Yellowstone National Park.

The trash haul includes some odd items

It is not just wrappers and lost caps appearing near Yellowstone’s hot springs. Staff have recovered objects ranging from camera parts and hotel keys to toys, sunglasses and hair accessories.

The 2026 collection also includes 6 Invisalign retainers, 15 fake nails and a lump of glittery pink children’s slime stuck to geyserite pieces, according to the Yellowstone Volcano Observatory report.

Some finds are almost unbelievably specific

This season, Yellowstone’s Geology team collected 5 AirPods, 3 Delta flight pins, an inhaler, 3 golf tees and an Uno card from hydrothermal areas around the park this season.

The team’s most common discoveries included 54 camera lens caps, 47 hair ties, 20 hotel key cards, 42 pencils and 36 pieces of sunglasses, according to park officials.

A few lost items became staff favorites

Some discoveries stood out enough to become Yellowstone Geology staff favorites. The 2026 list includes 7 instant or Polaroid pictures, with several showing the hydrothermal features where they were found.

Other memorable discoveries included 6 Yellowstone pressed pennies, 4 Pokémon cards or figurines and a tiny 2-inch copy of The Vampire Diaries, making this season’s cleanup surprisingly varied this year.

Coins can cause trouble in hot springs

Even coins can create problems for the features in Yellowstone’s hot springs and geysers. The park team collected more than $18 in coins during the 2026 summer season so far.

Throwing coins into hydrothermal features can damage microbial communities and clog vents, according to the Yellowstone Volcano Observatory. The coins included U.S. currency, pesos, yen, euros and Canadian dollars too.

Millions of visitors add to the challenge

Yellowstone’s cleanup numbers are tied to heavy visitation. The park receives more than 4.5 million visitors each year, and busy hydrothermal areas can collect debris from dropped or discarded items.

Wind can make the problem worse by carrying light objects across boardwalks and into nearby features. Staff remove foreign material because it can interfere with water flow or introduce chemicals.

Grand Prismatic has a colorful secret

Grand Prismatic Spring is Yellowstone’s largest hot spring, measuring roughly 200 to 330 feet across and more than 121 feet deep, according to the National Park Service.

Its striking colors come from thermophiles, microscopic organisms that thrive in hot environments. Different groups live at different temperatures around the spring, creating bands of yellow, orange and green colors.

Yellowstone has thousands of thermal features

Yellowstone is home to more than 10,000 hydrothermal features, including hot springs, geysers, mudpots and fumaroles. More than 500 of those features are geysers, the National Park Service reports officially.

These systems are connected to heat beneath the park. Groundwater moves through underground rock, becomes heated and returns toward the surface, creating these thermal features visitors can see aboveground today.

The park has been protected since 1872

Yellowstone has been protected as a national park since March 1, 1872. That legislation established Yellowstone as the first national park in the United States on that date historically.

The park covers about 2.2 million acres across Wyoming, Montana and Idaho. Most of its land, about 96%, lies in Wyoming, while smaller portions extend into Montana and Idaho today.

Want to explore more fascinating history? See what archaeologists uncovered at an ancient Native American village.

Yellowstone’s history began long before 1872

Yellowstone’s human history goes back far beyond the park’s creation. Archaeological evidence shows people have been connected to the Yellowstone region for thousands of years before 1872.

The National Park Service recognizes 27 associated tribes with historic and modern ties to Yellowstone. Their connections include travel, hunting, gathering, trade and cultural traditions linked to the landscape.

Fun fact: Yellowstone is the only place in the U.S. where bison have lived continuously since prehistoric times.

A tiny object can affect a big system

Lost objects are more than a cleanup story. The Geology team says outside material can damage hydrothermal features by clogging water supplies, blocking runoff channels or introducing chemicals or sediment.

That is why staff collect everything from tiny plastic pieces to rocks and sticks. Visitors can help by keeping belongings secure and placing trash in proper containers on trails safely.

Visitors can help protect the hot springs

The 2026 findings show how varied Yellowstone’s hydrothermal cleanup becomes. From hats and pencils to pressed pennies and Pokémon cards, nearly anything small enough to fall can appear there too.

For visitors, the simplest takeaway is practical: stay on designated boardwalks and trails, secure loose belongings and keep trash contained. Those habits help protect Yellowstone’s unusual thermal landscapes for visitors.

Little-known fact: Yellowstone Lake is the largest high-elevation lake in North America.

Morning Glory Pool shows why litter matters

Yellowstone’s Morning Glory Pool became known for a color change linked to objects and trash thrown into the feature over many years. Debris visibly affected its hydrothermal system over time.

Park staff have removed items from the pool, sometimes draining part of it to make cleanup easier. The Geology Program removes debris regularly from hydrothermal areas to help protect them.

Curious about Yellowstone’s other hydrothermal surprises? Take a look at what officials recently confirmed.

What’s the strangest thing you’d expect to find in Yellowstone’s hot springs? Share your guess in the comments.

This slideshow was made with AI assistance and human editing.

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