Hoover Dam Trivia
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50 free Hoover Dam trivia questions with answers — history quiz, new questions added Aug 2026.
47 free Hoover Dam trivia questions with answers. Hoover Dam is the Depression-era colossus that tamed the Colorado River, and this quiz covers the whole story. 50 questions run from where the dam actually sits (not Boulder Canyon) to the consortium that built it two years ahead of schedule, the high scalers who dangled off the canyon walls, the ice-water pipes that cooled three million cubic yards of concrete, and the myth about workers entombed in it. You will also get the naming feud between the Hoover and Roosevelt administrations, the Winged Figures and the star map at the dedication plaza, the two clocks that only disagree in winter, Lake Mead's bathtub ring, the 2010 bypass bridge, and the films from Superman to Transformers that have wrecked the dam on screen. Easy questions suit anyone who has driven US 93; the expert tier asks for the artist behind the terrazzo floors and the last name on the fatality list. Every answer was checked against Wikipedia and the Bureau of Reclamation's own Hoover Dam pages, and each question carries the sentence that backs it up.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Hoover Dam was built in which gorge of the Colorado River?
Black Canyon
Black Canyon is where the dam rose; a study had first recommended another canyon upstream, and the whole project kept that earlier canyon's name even after engineers moved the site.
Q 02Hoover Dam straddles the border between Nevada and which other state?
Arizona
Arizona is on the dam's eastern side; because the two states keep different time zones, a walk across the 45-foot-wide crest can move a visitor's watch by an hour.
Q 03Hoover Dam is roughly 30 miles southeast of which major city?
Las Vegas
Las Vegas, about 30 miles northwest, was a town of roughly 5,000 when the dam was approved; thousands of jobless men poured in and camped nearby, hoping to be hired.
Q 04Which president dedicated Hoover Dam without once mentioning Herbert Hoover's name?
Franklin D. Roosevelt
Franklin D. Roosevelt opened his dedication speech on September 30, 1935, with 'This morning I came, I saw and I was conquered' and never once spoke his predecessor's name.
Q 05Lake Mead and its shores became the first of which kind of U.S. park unit?
National recreation area
National recreation area was a new label when the Park Service took charge of the reservoir's shores; the country's first, it now draws millions of boaters and swimmers a year to a lake that didn't exist before the dam.
Q 06Hoover Dam rises about as high as a building of how many stories?
60 stories
60 stories is the usual comparison for its 726 feet; the world's tallest dam when it was finished, it is no longer even America's tallest, overtaken in 1968 by an earthfill dam in California.
Q 07What structural type of dam is Hoover Dam?
Concrete arch-gravity
Concrete arch-gravity describes Hoover: 660 feet thick at the base, its curved upstream face carries the water's thrust into the canyon walls while its sheer weight resists overturning.
Q 08Which state that Hoover Dam doesn't touch receives the largest share of its electricity?
California
California takes more than half of the dam's electricity; the project was meant to be self-supporting, with sales of its power paying back the cost of construction.
Q 09In the 2007 film Transformers, what does Hoover Dam secretly house?
Megatron's frozen body
Megatron's frozen body is kept inside the dam by the secret agency Sector Seven; in the film's backstory the dam was built around the AllSpark so its concrete would hide the cube's energy.
Q 10In which 2015 disaster film does a massive earthquake collapse the dam?
San Andreas
San Andreas (2015) stages its first big set piece at the dam, where Paul Giamatti's seismologist watches a quake tear it apart; the 1978 Superman had already burst it on screen.
Q 11Which California lake formed when the Colorado River burst through a canal in 1905, spurring calls for a dam?
Salton Sea
Salton Sea filled a dry basin when the river poured through a failed irrigation cut; the breach took about two years and $3 million to close, and became the standing argument for a big dam upstream.
Q 12Which town was built specifically to house Hoover Dam's construction workers?
Boulder City
Boulder City was run as a federal reservation: a government-appointed manager could evict anyone he chose, and alcohol and gambling were banned outright.
Q 13Lake Mead holds which US record?
Largest reservoir by volume
Q 21Hoover Dam's official death toll of 96 leaves out 42 workers whose deaths were recorded as which illness?
Pneumonia
Pneumonia was the recorded cause for 42 workers left off the official list, which counts only accidents at the site such as falls, blasts and rockslides; deaths from heat or illness were never included.
Q 22Which Interior Secretary ordered in 1933 that the Hoover name be dropped from the dam?
Harold L. Ickes
Harold L. Ickes, widely thought to dislike Hoover, said the dam's pioneers had known it by its old project name; in fact Congress had already written Hoover's name into five spending bills.
Q 23Which president signed the resolution that restored Herbert Hoover's name to the dam?
Harry S. Truman
Largest reservoir by volume in the United States when full, Lake Mead last topped its spillway gates in 1983; long drought has since pulled it to its lowest levels since it first filled.
Q 14Which firm won the contract to build Hoover Dam in 1931?
Six Companies, Inc.
Six Companies, Inc. pooled builders such as Bechtel, Kaiser and Morrison-Knudsen because none could post the bond alone; its bid of about $48.9 million landed within $24,000 of the government's own estimate.
Q 15Which superintendent drove Hoover Dam's construction to finish two years ahead of schedule?
Frank Crowe
Frank Crowe got into dam building as a Maine engineering student, signing up for a summer job with the Reclamation Service before a guest lecture had ended; he stayed for 20 years.
Q 16What were the Hoover Dam workers called who dangled from ropes to blast loose rock off the canyon walls?
High scalers
High scalers hung from ropes to drill and blast loose rock from the canyon walls; they swung out to perform stunts when foremen weren't looking, and one once caught a falling engineer in midair.
Q 17Which safety gear did Hoover Dam workers improvise from cloth and coal tar?
Hard hats
Hard hats at the dam began as cloth hats that workers coated in coal tar; after men struck by falling rock broke their jaws but not their skulls, the contractor ordered factory-made ones by the thousands.
Q 18Had Hoover Dam been poured as one continuous mass, how long did engineers calculate the concrete would take to cool?
125 years
125 years was the estimate for a single pour, and the stresses would have cracked the dam; so it rose as interlocking blocks laced with pipes that carried river water, then refrigerated water, through each one.
Q 19During World War II, how did civilian traffic cross Hoover Dam?
In escorted convoys
In escorted convoys: the dam shut to visitors on the day of Pearl Harbor and stayed closed until 1945, because its power fed wartime aircraft factories and soldiers guarded every crossing.
Q 20Each pour raised a Hoover Dam block by mere inches, a fact that debunks which legend?
Entombed workers
Entombed workers are a legend the dam's operators flatly deny: a crew of men stamped down every fresh layer of concrete, so a body could not have gone unnoticed.
Harry S. Truman signed it on April 30, 1947; the Democrat had already brought the former Republican president back into public life to lead relief missions after World War II.
Q 24Which president signed the act authorizing Hoover Dam?
Calvin Coolidge
Calvin Coolidge signed the act in December 1928, while Herbert Hoover was president-elect; its $165 million price tag had helped stall the bill in Congress for six years.
Q 25Architect Gordon Kaufmann swapped the engineers' eagles and cornices on Hoover Dam for which style?
Art Deco
Art Deco replaced the ornament the engineers had planned: Kaufmann, an English-born Los Angeles architect, left the dam's curved face bare and smoothed its towers so the structure itself did the work.
Q 26What are the two bronze statues flanking Hoover Dam's flagpole called?
Winged Figures of the Republic
Winged Figures of the Republic were each cast in one continuous pour of bronze; their sculptor gave them 'the look of eagles' because, he wrote, building the dam belonged 'to the sagas of the daring'.
Q 27The terrazzo star map at Hoover Dam freezes the sky on which date?
The dam's dedication
The dam's dedication on September 30, 1935, is set into the floor so exactly that astronomers could work out the date from the star positions alone, even thousands of years from now.
Q 28Before politics, Hoover Dam's namesake made his fortune in which profession?
Mining engineer
Mining engineer was Herbert Hoover's first career and made him a millionaire before 40, which is why the Interior Secretary who named the dam in 1930 called him 'the great engineer'.
Q 29The bridge that bypasses Hoover Dam is co-named for which former NFL player?
Pat Tillman
Pat Tillman walked away from a pro football career to enlist in the Army in 2002 and was killed in Afghanistan in 2004; the bridge's other namesake, Mike O'Callaghan, was a Nevada governor and Korean War veteran.
Q 30Lake Mead is named for Elwood Mead, who held what job?
Reclamation commissioner
Reclamation commissioner was Elwood Mead's post from 1924 until he died in office in January 1936; he had earlier drafted Wyoming's water laws, and the new lake was named in his honor.