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49 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 49 questions with answers and explanations. Play the quiz
Q 01Crater Lake National Park is in which US state?
Oregon
Oregon's only national park, Crater Lake lies in the southern Cascade Range north-east of Medford; its lake is the deepest in the United States.
Q 02Crater Lake fills the caldera of which collapsed volcano?
Mount Mazama
Mount Mazama, a stratovolcano in the southern Cascades, grew over hundreds of thousands of years before its summit collapsed into the emptied magma chamber; the Klamath people witnessed the eruption and kept its memory in legend.
Q 03How deep is Crater Lake at its deepest point?
1,949 feet
1,949 feet (594 m) was the maximum depth measured by a 2000 multibeam sonar survey, making Crater Lake the deepest lake in the United States; its average depth is about 1,148 feet.
Q 04How is Crater Lake refilled, given that no streams flow into or out of it?
Entirely by rain and snow falling on it
Entirely by rain and snow falling on it, the lake is kept at a nearly constant level because evaporation and seepage balance the precipitation; with no streams carrying in sediment, it is among the clearest lakes on Earth.
Q 05Roughly how long ago did the climactic eruption and collapse create the caldera?
About 7,700 years ago
About 7,700 years ago (around 5700 BC) the volcano's climactic eruption emptied its magma chamber and the summit collapsed; ash from the blast forms a dated marker layer across the Pacific Northwest.
Q 06The surface of Crater Lake lies at roughly what elevation above sea level?
About 6,180 feet
About 6,180 feet (1,883 m) is the elevation of the lake surface, whose level varies only a few feet from year to year because precipitation is balanced by evaporation and seepage.
Q 07Roughly how much rock and ash did the climactic eruption eject?
About 50 cubic kilometres
About 50 cubic kilometres (12 cubic miles) of magma erupted as ash and pumice, dozens of times the output of Mount St. Helens in 1980; the ash layer is found across the Pacific Northwest and into Canada.
Q 08The volcanoes of the Cascades are fed by the subduction of which piece of oceanic crust?
Juan de Fuca Plate
The Juan de Fuca Plate, a small remnant of the ancient Farallon Plate, slides beneath the North American Plate off the Pacific Northwest coast; hydrothermal vents on the lake floor show the volcano is dormant, not extinct.
Q 09What is Wizard Island?
A cinder cone that rose after the caldera formed
A cinder cone that rose after the caldera formed, Wizard Island erupted onto the caldera floor while the lake was filling and rises about 755 feet above the water; summer boat tours land there.
Q 10What did William Gladstone Steel name the crater on top of Wizard Island in 1885?
The Witches Cauldron
The Witches Cauldron was Steel's name for the crater at the island's summit, which he named Wizard Island on the same 1885 visit because its shape recalled a wizard's hat; a trail climbs to the crater rim.
Q 11Why can't visitors see Merriam Cone, a volcanic cone in the north-east of the lake?
Its summit is about 500 feet under water
Its summit is about 500 feet under water: Merriam Cone, a volcanic cone on the caldera floor, erupted while the lake was filling, and its smooth, craterless surface shows it was built under water rather than in air.
Q 12Phantom Ship, the small jagged island in the southeast of the lake, is made of rock roughly how old?
About 400,000 years
About 400,000 years old, Phantom Ship's andesite is the oldest exposed rock in the caldera, a remnant of an early cone; seen in fog or low light the jagged island looks like a ghostly sailing ship.
Q 13The Old Man of the Lake is what?
Q 21How much snow falls on the park in an average year?
About 463 inches
About 463 inches, roughly 39 feet, falls on park headquarters in an average year, among the highest totals at any long-term US weather station; drifts of 10 to 15 feet linger on the rim into late spring.
Q 22When did the lake last freeze over completely?
1949
1949 saw the last complete freeze; the lake's great depth stores summer heat and mild Pacific air keeps winters moderate, so ice rarely forms, and a 1985 freeze covered only about 95 percent of the surface.
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
A tree trunk that has floated upright since at least 1896, the Old Man of the Lake is a 30-foot mountain hemlock stump first recorded by geologist Joseph Diller; 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
At least 62 miles: tracked between July and September 1938, the stump covered 62.1 miles, moving fastest on windy days; geologist Joseph Diller had shown it drifted by tethering it 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
'Deep Blue Lake' was the name chosen by John Wesley Hillman, Henry Klippel and Isaac Skeeters, prospectors hunting for a lost gold mine; the spot where they first saw it on 12 June 1853 became 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
From a newspaper article wrapped around his lunch, Steel read of the lake as a schoolboy in 1870; he first saw it in 1885, walking the last 20 miles from Fort Klamath, and spent 17 years lobbying for a park.
Q 17How did the 1886 USGS expedition measure the lake's depth?
A pipe on piano wire from a survey boat
A pipe on piano wire from a survey boat — a half-ton craft hauled up the mountain — gave 168 soundings; the deepest, 1,996 feet, came remarkably close to the modern sonar figure.
Q 18Which president signed the act creating Crater Lake National Park on 22 May 1902?
Theodore Roosevelt
Theodore Roosevelt signed the bill on 22 May 1902, making Crater Lake the first national park created during his presidency; Steel's lobbying and the 1886 survey data had made the case.
Q 19The mountaineering club that christened the volcano took its own name from which animal?
Mountain goat
Mountain goat is the meaning of 'mazama', the name the Portland climbing club adopted at its founding on the summit of Mount Hood in July 1894; the club's later convention at the lake named the volcano after itself.
Q 20In Klamath legend, Llao of the Below World battled which chief of the Above World?
Skell
Skell, chief of the Above World, defeated Llao in a battle of hurled rocks and fire that destroyed Llao's mountain home, a story matching the geological record; Llao Rock and Skell Head on the rim carry 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
Kokanee salmon and rainbow trout are the two species that survived from decades of stocking that began in 1888; the lake is believed to have had no native fish, and anglers need no licence there.
Q 25What is the only way for visitors to reach the lake shore?
Hiking down the steep Cleetwood Cove Trail
Hiking down the steep Cleetwood Cove Trail, a 1.1-mile path that drops about 700 feet at an 11 percent grade, is the sole route to the water; swimming is allowed at the bottom, where the boat dock also lies.
Q 26How were the tour boats on Crater Lake delivered to the water?
By helicopter
By helicopter: with no road to the shore, each tour boat was slung beneath a helicopter and lowered onto the lake; the boats stop at Wizard Island on summer tours.
Q 27How long is the Rim Drive that circles the caldera?
33 miles
33 miles long, Rim Drive circles the caldera with some 30 overlooks; because of the deep snowpack it is usually fully open only from July to October.
Q 28What is the highest point in the park?
Mount Scott
Mount Scott, at 8,929 feet, is a satellite cone on the park's eastern edge, reached by a 2.5-mile trail; from the summit the whole caldera is visible, and on clear days the view stretches more than 100 miles.
Q 29Llao Rock on the north side rises how far above the lake?
About 1,800 feet
About 1,800 feet above the water, Llao Rock is a thick rhyodacite lava flow that filled an explosion crater not long before the climactic eruption and was sliced through by the caldera collapse, exposing its cross-section.
Q 30What historic structure, built in 1932, stands at the top of the Watchman Peak trail?
A fire lookout tower
A fire lookout tower, the Watchman Lookout Station, was built on the 8,013-foot summit in 1932 in the rustic style and is listed on the National Register; the 0.8-mile trail climbs from the west side of Rim Drive.