50 free Crater Lake National Park trivia questions with answers — geography quiz, new questions added Aug 2026.
This Crater Lake National Park trivia quiz covers Oregon's only national park and the astonishing blue lake that fills the caldera of Mount Mazama. Questions cover the geology (the eruption 7,700 years ago that dropped the mountain a mile, the ash that reached Yellowstone, the cinder cone that became Wizard Island), the numbers (1,949 feet deep, 463 inches of snow a year, water so clear a disc was seen 142 feet down) and the wildlife and forests around the rim. The history includes the Klamath legend of Llao and Skell, the gold prospectors who found 'Deep Blue Lake' in 1853, William Gladstone Steel's 17-year campaign after reading about the lake on a newspaper wrapped round his lunch, the 1886 sounding expedition with piano wire, Theodore Roosevelt's 1902 signature, the lodge that nearly collapsed and the Old Man of the Lake, a hemlock trunk that has bobbed upright since at least 1896. Questions run from easy to expert with the difficulty shown on each one. Every answer was checked against a reference page and each question carries its citation. If you enjoy this one, try our Yellowstone and US National Parks quizzes next.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Crater Lake National Park is in which US state?
Oregon
It is the state's only national park and, established in 1902, the fifth-oldest in the country.
Q 02Crater Lake fills the caldera of which collapsed volcano?
Mount Mazama
The mountain once stood around 12,000 feet, which would have made it the state's highest peak; the Klamath called it Tum-sum-ne.
Q 03How deep is Crater Lake at its deepest point?
1,949 feet
That makes it the deepest lake in the United States and the second-deepest in North America after Canada's Great Slave Lake.
Q 04How is Crater Lake refilled, given that no streams flow into or out of it?
Entirely by rain and snow falling on it
Water leaves only by evaporation and seepage, which is why the lake is among the purest and clearest on Earth.
Q 05Roughly how long ago did the climactic eruption and collapse create the caldera?
About 7,700 years ago
The blast was the largest in the Cascades in a million years and left a hole about 4,000 feet deep that took roughly 740 years to fill.
Q 06How much height did the volcano lose when it collapsed?
About 2,500 to 3,500 feet
The summit fell into the emptied magma chamber; today the caldera rim stands between 7,000 and 8,000 feet.
Q 07How did the ash output of the climactic eruption compare with the 1980 eruption of Mount St. Helens?
More than 150 times as much
Ash fell as far as the northwest corner of Yellowstone, central Nevada and southern British Columbia, and weathered into a soil called andisol.
Q 08The volcanoes of the Cascades are fed by the subduction of which piece of oceanic crust?
Juan de Fuca Plate
It slides beneath the North American Plate off the coast; hydrothermal activity on the lake floor suggests Mazama may erupt again someday.
Q 09What is Wizard Island?
A cinder cone that rose after the caldera formed
It rises about 755 feet above the water and 2,700 feet above the deepest point of the caldera floor; boat tours stop there in summer.
Q 10What did William Gladstone Steel name the crater on top of Wizard Island in 1885?
The Witches Cauldron
The summit crater is about 500 feet wide and 100 feet deep; he named the island itself on the same trip.
Q 11A second large cinder cone, Merriam Cone, lies in the northeast of the lake. Why can't you see it?
Its summit is about 500 feet under water
Its smooth surface and lack of a crater show it erupted underwater as the lake was filling.
Q 12Phantom Ship, the small jagged island in the southeast of the lake, is made of rock roughly how old?
About 400,000 years
The andesite is part of a submerged older cone; the island looks like a ghostly sailing ship in fog and low light.
Q 13The Old Man of the Lake is what?
Q 21How much snow falls on the park in an average year?
About 463 inches
Headquarters sees snow more often than any other long-term station in the state; the record year, 1950, brought 903 inches, and drifts reach 10 to 15 feet by spring.
Q 22When did the lake last freeze over completely?
1949
Its huge depth stores heat and mild Pacific air helps; a 95 percent freeze happened in 1985. The bottom stays at about 38 °F all year.
Q 23What record clarity depth did scientists measure with a Secchi disc in 1997?
142 feet
Typical readings are about 120 feet; a 2025 reading of just 78 feet raised concern that the water is getting cloudier.
A tree trunk that has floated upright since at least 1896
The 30-foot hemlock stump bobs vertically around the lake; carbon dating suggests the tree is at least 450 years old.
Q 14How far did the Old Man of the Lake travel during three months of tracking in 1938?
At least 62 miles
It moves fastest on windy days; geologist Joseph Diller had first proved it drifted by towing it with baling wire and finding it a quarter-mile away five years later.
Q 15What name did the three gold prospectors who found the lake in June 1853 give it?
Deep Blue
John Wesley Hillman, Henry Klippel and Isaac Skeeters were hunting for provisions; the spot where they first saw it is now Discovery Point.
Q 16How did William Gladstone Steel first learn of Crater Lake as a Kansas schoolboy in 1870?
From a newspaper article wrapped around his lunch
He did not see the lake until 1885, walking the last 20 miles from Fort Klamath, then spent 17 years lobbying Congress.
Q 17How did the 1886 USGS expedition measure the lake's depth?
A pipe on piano wire from a survey boat
They hauled the half-ton boat Cleetwood up the mountain and took 168 soundings; the deepest, 1,996 feet, was remarkably close to the modern sonar figure.
Q 18Which president signed the act creating Crater Lake National Park on 22 May 1902?
Theodore Roosevelt
Steel's lobbying and the 1886 survey data made the case; the lodge followed in 1915 and Rim Drive in 1918.
Q 19At the 1896 Mazamas mountaineering convention, what did the assembled crowd do on the rim?
Christened the vanished volcano 'Mount Mazama'
Fireworks were lit on Wizard Island; the Klamath had their own name for the place for 10,000 years.
Q 20In Klamath legend, Llao of the Below World battled which chief of the Above World?
Skell
The fight destroyed Llao's home, the mountain, a story that closely mirrors what geologists have since worked out; Llao Rock and Skell Head bear their names.
Q 24Which fish thrive in the lake, which is believed to have had no native fish at all?
Kokanee salmon and rainbow trout
Stocking began in 1888 and ended in 1941; since then fishing there has needed no licence and had no limits on size or number.
Q 25What is the only way for visitors to reach the lake shore?
Hiking down the steep Cleetwood Cove Trail
The 1.1-mile trail drops 656 feet at an 11 percent grade; every boat on the lake had to be flown in.
Q 26How were the tour boats on Crater Lake delivered to the water?
By helicopter
There is no road to the shore, so the concessionaire's boats came in by air; they stop at Wizard Island on summer tours.
Q 27How long is the Rim Drive that circles the caldera?
33 miles
It climbs 3,800 feet in total and is usually fully open only from July to October because of snow.
Q 28What is the highest point in the park?
Mount Scott
At 8,929 feet it is a parasitic cone fed from Mazama's magma chamber; from the top you can see the whole caldera and more than 100 miles.
Q 29Llao Rock on the north side rises how far above the lake?
About 1,800 feet
A 1.3-mile trail from Rim Drive reaches its summit; the lodge on the opposite rim sits about 1,000 feet above the water.
Q 30The Watchman Peak trail ends at a historic structure built in 1932. What is it?
A fire lookout tower
From the summit you can see Mount McLoughlin, Mount Thielsen, Union Peak and the Klamath Basin.