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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 the gorge where the dam rose; engineers chose it over the canyon first surveyed upstream for its narrower walls and sounder bedrock, though the project kept the earlier canyon's name.
Q 02The dam straddles the border between Nevada and which other state?
Arizona
Arizona is on the dam's eastern side; the state line crosses the crest, and the intake towers carry one clock showing Nevada time and another showing Arizona time.
Q 03The dam is roughly 30 miles southeast of which major city?
Las Vegas
Las Vegas lies about 30 miles northwest of the dam; the city lobbied to be construction headquarters and even shut its speakeasies during the Interior Secretary's visit, but a purpose-built town got the job.
Q 04Which president formally dedicated the dam on September 30, 1935?
Franklin D. Roosevelt
Franklin D. Roosevelt dedicated the dam on September 30, 1935, declaring 'I came, I saw, and I was conquered' in a speech broadcast nationwide by radio.
Q 05Under what official name was the dam dedicated in 1935?
Boulder Dam
Boulder Dam was the name the Interior Department adopted in 1933 and used at the 1935 dedication; the three-cent commemorative stamp issued for the ceremony reads 'Boulder Dam'.
Q 06How tall is the dam from foundation rock to the roadway on its crest?
726 feet
The dam stands 726 feet from foundation rock to the roadway on its crest, which made it the tallest dam in the world when it was completed in 1936.
Q 07What structural type of dam is Hoover?
Concrete arch-gravity
Concrete arch-gravity describes Hoover: 660 feet thick at the base and 45 feet at the crest, its curved upstream face carries the water's thrust into the canyon walls while its sheer mass resists overturning.
Q 08What is the rated generating capacity of the Hoover Dam power plant?
2,080 MW
2,080 MW is the rated capacity of the Hoover power plant, whose generators sit in a U-shaped powerhouse at the dam's base and supply customers in three states.
Q 09In the 2007 film Transformers, what does the dam secretly house?
Megatron's frozen body
Megatron's frozen body is hidden inside the dam by the secret agency Sector Seven, which also keeps the AllSpark there; the Decepticons converge on the dam to thaw their leader.
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 highway ran across the dam's crest before the bypass bridge opened?
U.S. Route 93
U.S. Route 93 ran across the dam's crest for decades; after the 2001 attacks, truck traffic was restricted, and the highway moved onto the bypass bridge when it opened in 2010.
Q 12Which town was built specifically to house the dam's construction workers?
Boulder City
Boulder City was built by the federal government in 1931 to house dam workers under strict rules; it banned gambling from the start and kept the ban long after the dam was done.
Q 13Lake Mead holds which US record?
Largest reservoir by volume
Q 21What is the Bureau of Reclamation's official count of construction fatalities?
96
96 is the Bureau's official industrial fatality count; broader tallies reach 112 by adding deaths away from the site, such as a 1922 surveying drowning during early river studies.
Q 22Which Interior Secretary ordered in 1933 that the dam stop carrying Hoover's name?
Harold L. Ickes
Harold L. Ickes, the New Deal Interior Secretary, struck Hoover's name from the dam in 1933, a partisan slap at the outgoing Republican president, and pointedly avoided the name at the 1935 dedication.
Q 23In what year did Congress unanimously restore the name Hoover Dam?
1947
1947 is when Congress unanimously voted to restore the Hoover Dam name, and President Truman signed the resolution that April, ending a fourteen-year naming feud.
Largest reservoir by volume in the United States is Lake Mead's distinction: at full pool it stretches about 112 miles, reaches roughly 530 feet deep and stores roughly 28 million acre-feet.
Q 14Which consortium won the contract to build the dam in 1931?
Six Companies, Inc.
Six Companies, Inc., a consortium that included Bechtel, Kaiser, Utah Construction and Morrison-Knudsen, won with a bid of $48,890,955, within $24,000 of the government's confidential estimate.
Q 15Who was the general construction superintendent who ran the job for the contractor?
Frank Crowe
Frank Crowe, the contractor's general superintendent, had spent his career building Reclamation dams and pioneered overhead cableways for delivering concrete; he later ran construction of Shasta Dam in California.
Q 16What were the 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, a risky, well-paid job that drew sightseers to watch their swinging acrobatics.
Q 17Which piece of safety gear did workers improvise at the dam by dipping cloth caps in tar?
Hard hats
Hard hats at the dam began as cloth caps dipped in tar and hardened, nicknamed 'hard-boiled hats'; after the homemade versions saved men from falling rock, the contractor ordered thousands of manufactured ones.
Q 18Had the dam been poured as one continuous mass, how long did engineers calculate the concrete would take to cool?
125 years
125 years was the estimated cooling time for a single monolithic pour, so the dam was built as interlocking blocks threaded with pipes carrying chilled water from an on-site refrigeration plant.
Q 19How much 1-inch steel cooling pipe was embedded in the concrete?
More than 582 miles
More than 582 miles of 1-inch steel pipe was laid through the blocks, fed first with river water and then with refrigerated water from a plant able to make 1,000 tons of ice a day.
Q 20According to the Bureau of Reclamation, how many workers are buried inside the dam's concrete?
None
None of the workers is entombed in the dam: each bucket raised a block's level by only about an inch, and crews of 'puddlers' worked every pour, so a body could not have gone unnoticed.
Q 24Which president signed the 1928 act that authorized the dam?
Calvin Coolidge
Calvin Coolidge signed the Boulder Canyon Project Act on December 21, 1928; it authorized $165 million for the dam and for the All-American Canal serving California's Imperial Valley.
Q 25Which architect gave the dam its streamlined Art Deco look after the first plans were called too plain?
Gordon B. Kaufmann
Gordon B. Kaufmann, a Los Angeles architect, streamlined the dam's look after the Bureau's first plans, with a Gothic-inspired balustrade and eagle statues, were judged unworthy of so grand a structure.
Q 26What are the two 30-foot bronze statues at the dedication plaza called?
Winged Figures of the Republic
Winged Figures of the Republic are the two 30-foot bronzes flanking the flagpole; each was cast in one continuous pour and slid into place on blocks of ice to protect the polished metal.
Q 27What does the terrazzo star map at the base of the plaza's flagpole monument record?
The sky at the moment of the dam's dedication
The sky at the moment of the dam's dedication is what the star map fixes, laid out so precisely that astronomers far in the future could work out the exact date even if written records were lost.
Q 28Where did the four-lane Hoover Dam Bypass bridge, opened in October 2010, cross the river?
About 1,500 feet downstream
About 1,500 feet downstream of the dam, the bridge carries the highway roughly 900 feet above the river; through traffic across the crest ended when it opened, though the dam itself stayed open to visitor traffic.
Q 29The bypass bridge is co-named for which NFL player killed in Afghanistan in 2004?
Pat Tillman
Pat Tillman gave up an NFL safety's career with the Cardinals to enlist after 9/11 and died in Afghanistan in 2004; the bridge's other namesake, Mike O'Callaghan, was Nevada's governor from 1971 to 1979.
Q 30Lake Mead is named for Elwood Mead, who held what job?
Reclamation commissioner
Reclamation commissioner was Elwood Mead's post from 1924 until his death in January 1936, spanning the planning and construction of the dam; the reservoir was named for him that year.