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
The site was originally expected to be Boulder Canyon, 20 miles upstream, and the project kept the 'Boulder Canyon Project' name even after engineers moved it.
Q 02The dam straddles the border between Nevada and which other state?
Arizona
The state line runs across the crest, and each side has its own clock face on the intake towers.
Q 03The dam is roughly 30 miles southeast of which major city?
Las Vegas
The city lobbied hard to be the construction headquarters and even shut its speakeasies when the Interior Secretary visited, but lost out to a purpose-built town.
Q 04Which president formally dedicated the dam on September 30, 1935?
Franklin D. Roosevelt
The ceremony was moved up three hours the morning of the event because a reserved radio slot turned out to be 2 p.m. Eastern, not Pacific.
Q 05What was the dam's official name between 1933 and 1947?
Boulder Dam
The three-cent stamp issued for the 1935 dedication carried the alternative name rather than the one used today.
Q 06How tall is the dam from foundation rock to the roadway on its crest?
726 feet
The towers and ornaments on the parapet add another 40 feet above the crest.
Q 07What structural type of dam is Hoover?
Concrete arch-gravity
It is thick at the bottom and thin at the top, with a convex face that pushes the water's force into the canyon walls.
Q 08Roughly how many tourists visit the dam each year?
7 million
Nearly a million of them take the paid Bureau of Reclamation tours; the rest see it from the crest and the visitor center.
Q 09In the 2007 film Transformers, what does the dam secretly house?
Megatron's frozen body
The Decepticons attack the dam during the film to retrieve their frozen leader.
Q 10In which 2015 disaster film does a massive earthquake collapse the dam?
San Andreas
The 1978 Superman film also destroyed it on screen, that time after a nuclear bomb triggered the San Andreas Fault.
Q 11Which Griswold family comedy features Clark springing a leak inside the dam's walkways?
Vegas Vacation
The 1997 film had the family visit the dam on a side trip from the Strip.
Q 12Which town was built specifically to house the dam's construction workers?
Boulder City
Gambling has been banned there since it was founded, making it one of only two places in Nevada where you cannot legally gamble.
Q 13Lake Mead holds which US record?
Largest reservoir by volume
At full pool it stretches 112 miles, reaches 532 feet deep, and holds over 28 million acre-feet of water.
Q 21What is the Bureau of Reclamation's official count of construction fatalities?
96
Broader tallies reach 112 by counting a 1922 surveying drowning and other deaths outside the site.
Q 22Which Interior Secretary ordered in 1933 that the dam stop carrying Hoover's name?
Harold L. Ickes
At the 1935 dedication he pointedly used the rival name five times in thirty seconds, and he still opposed the later restoration as a private citizen.
Q 23In what year did Congress unanimously restore the name Hoover Dam?
1947
By then many Americans used both names interchangeably and mapmakers were split over which to print.
Q 14Which consortium won the contract to build the dam in 1931?
Six Companies, Inc.
Its bid of $48,890,955 came 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
He earned two patents for the giant concrete buckets used on the job and went on to build Shasta Dam in California.
Q 16What were the workers called who dangled from ropes to blast loose rock off the canyon walls?
High scalers
They became a tourist attraction in their own right, and one was nicknamed the 'Human Pendulum' for swinging co-workers across the canyon.
Q 17Which piece of safety gear did workers improvise at the dam by dipping cloth caps in tar?
Hard hats
Men struck hard enough to break their jaws walked away without skull injuries, so the contractor ordered thousands of them.
Q 18Had the dam been poured as one continuous mass, how long did engineers calculate the concrete would take to cool?
125 years
Instead it was poured as interlocking blocks threaded with cooling pipes carrying ice water from an on-site refrigeration plant.
Q 19How much 1-inch steel cooling pipe was embedded in the concrete?
More than 582 miles
The refrigeration plant that chilled the water could produce 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
Each bucket raised the level in a form 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
The act appropriated $165 million and also covered the downstream Imperial Dam and All-American Canal.
Q 25Which architect gave the dam its streamlined Art Deco look after the first plans were called too plain?
Gordon B. Kaufmann
The Bureau's original design had a Gothic-inspired balustrade and eagle statues before he was brought in.
Q 26What are the two 30-foot bronze statues at the dedication plaza called?
Winged Figures of the Republic
Each was cast in a single continuous pour and then slid into place on blocks of ice to protect the polished bronze.
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
It was laid out so precisely that future astronomers 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
Through traffic across the crest ended when it opened; visitors can still drive over to the parking lots on the far side.
Q 29The bypass bridge is co-named for which NFL player killed in Afghanistan in 2004?
Pat Tillman
The other honoree, 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
He held the post from 1924 to 1936, spanning the planning and construction of the entire Boulder Canyon Project.