Idaho Falls
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40 free Idaho Falls trivia questions with answers — geography quiz, new questions added Oct 2026.
Idaho Falls looks like a quiet farm-country city on the Snake River, but its story is stranger than that. It began as a river crossing for wagon freighters, nearly emptied out when the railroad changed its plans, and later found itself next door to some of the most important reactor experiments ever run. This quiz covers the city's frontier beginnings and its old name, the atomic-age history made in the desert to the west, and the everyday landmarks locals know: the ballpark, the zoo, the museum, the temple by the river. There are also questions on eastern Idaho geography and on the writers, broadcasters and athletes with ties to the city. It is pitched for residents, former residents and visitors, with plenty of questions a curious outsider can reason out. Every answer comes with a short explanation, so you will leave knowing a little more about the place.
30 of 40 questions with answers and explanations. Play the quiz
Q 01In 1951 the EBR-I reactor in the desert west of Idaho Falls made nuclear history by powering what?
Four light bulbs
Four light bulbs of 200 watts each glowed on December 20, 1951, and a day later the breeder reactor was supplying its whole building.
Q 02What was Idaho Falls called until 1891, when promoters renamed it for rapids on the Snake River?
Eagle Rock
Eagle Rock came from an island in the river where about twenty eagles nested; the settlement had started out as Taylor's Crossing.
Q 03The waterfalls at Idaho Falls took shape only after a retaining wall was built for what?
A hydroelectric plant
A hydroelectric plant needed the wall, which turned what had been rapids into falls some years after the city had already taken its name.
Q 04Which author wrote Where the Red Fern Grows after working construction near Idaho Falls?
Wilson Rawls
Wilson Rawls burned his manuscripts before marrying a woman he met there; she urged him to rewrite one, and he reportedly finished it in three weeks.
Q 05Which small Idaho town became, in 1955, the first community anywhere lit solely by nuclear power?
Arco
Arco ran for about an hour on July 17, 1955, on electricity from the experimental BORAX-III reactor at the testing station next door.
Q 06The Idaho Falls Pioneer League baseball club took its name, by fan vote, from which game bird?
Chukar
Chukar partridges, native to Asia, now live wild in the region; fans chose the name after the 2003 season, when the club's major league affiliation changed.
Q 07Which Idaho dam collapsed in June 1976 as it first filled, sending a flood toward Idaho Falls?
Teton
Teton Dam's failure killed 11 people and thousands of livestock; Idaho Falls, farther down the flood plain, had time to prepare.
Q 08After the Emotion Bowl between Idaho Falls and Skyline high schools, what do the winners paint?
The goalposts
The goalposts turn orange for an Idaho Falls High win or blue for Skyline, painted by the winning team and its fans once the game is over.
Q 09Which U.S. military branch trained nearly 40,000 personnel at a reactor facility near Idaho Falls?
Navy
Navy crews learned to run ship and submarine power plants on prototypes built far from any ocean, from the early 1950s to the mid-1990s.
Q 10What delayed the dedication of the Idaho Falls Idaho Temple, whose exterior was finished in 1941?
World War II
World War II shortages stalled work on the interior, and the temple was finally dedicated one month after the fighting ended.
Q 11Idaho Falls is twinned with Tokai, a town built around nuclear research, in which country?
Japan
Japan saw its first nuclear reactor go critical in Tokai, a fitting partner for a city that grew up beside a reactor testing station.
Q 12What did Matt Taylor build across the Snake River in the 1860s, founding the future Idaho Falls?
A toll bridge
A toll bridge of timber spanned a narrow gorge, speeding miners and freighters north, and by the end of 1865 a bank, hotel and stage station stood beside it.
Q 13Idaho Falls nearly died in 1887 when the railroad moved most of its facilities to which city?
Pocatello
Pocatello gained the shops after a railroad workers' strike, and the sharp, immediate drop in population nearly killed the older town.
Q 21Which junior hockey team was founded in 2022 to play at a newly built arena in Idaho Falls?
Spud Kings
Spud Kings was the name given to an expansion franchise approved in March 2022, eight months before its home arena opened to the public.
Q 22When Idaho Falls joined baseball's Pioneer League in 1940, its team took which potato nickname?
Russets
Russets was the choice in 1940; the club later played as the Yankees, Angels, Braves and Padres as its major league partners changed.
Q 23Which wellness company, long led by Frank VanderSloot, paid to finish the Idaho Falls ballpark?
Melaleuca
Melaleuca put up $600,000 to cover a late budget shortfall, and the rebuilt park, dedicated in June 2007, has carried the company's name ever since.
Q 14Which Gilded Age financier backed the Utah and Northern Railway, which reached Idaho Falls in 1879?
Jay Gould
Jay Gould stood behind the line through Union Pacific, which had bought the bankrupt railroad and was driving it north to the copper mines at Butte.
Q 15Early wagon traffic crossing the river at Idaho Falls was bound for gold fields in which territory?
Montana
Montana boom towns such as Bannack and Virginia City pulled miners and freighters north along a wagon road that began in Salt Lake City.
Q 16Which interstate highway passes through Idaho Falls on its long run north from San Diego?
I-15
I-15 enters Idaho from Utah and leaves over Monida Pass, covering 196 miles down the eastern side of the state.
Q 17Which newspaper is based in Idaho Falls, formed when two rival local papers merged?
Post Register
Post Register became the masthead in 1931, when the owners of the Idaho Falls Post bought the rival Times-Register and merged the two papers.
Q 18Which Idaho Falls city park holds the zoo, the Funland amusement rides and an ice arena?
Tautphaus
Tautphaus Park began as the ranch of Charles Tautphaus, who dug canals and a reservoir to water his desert claim; the city bought the land in the 1930s.
Q 19The Museum of Idaho in Idaho Falls grew out of a library funded by which industrialist?
Andrew Carnegie
Andrew Carnegie's foundation granted $15,000 in 1913 to a women's club, the Village Improvement Society; the old library was later saved from demolition.
Q 20The Snake River, which flows through Idaho Falls, is the largest tributary of which river?
Columbia
Columbia water carries the Snake to the Pacific; the two rivers meet in Washington after the Snake has run about 1,080 miles.
Q 24The fatal 1961 SL-1 reactor accident near Idaho Falls began when an operator pulled what too far?
A control rod
A control rod meant to be lifted only a few inches came out roughly twenty, and the Army reactor went prompt critical in milliseconds, killing all three men present.
Q 25Locals in Idaho Falls call the vast Idaho National Laboratory complex by what short nickname?
The Site
The Site sprawls over 890 square miles of high desert, where more than 50 reactors have been built, the largest concentration in the world.
Q 26Idaho National Laboratory, a major employer for Idaho Falls, belongs to which federal department?
Energy
Energy inherited the laboratory, which the Atomic Energy Commission opened in 1949 as the National Reactor Testing Station.
Q 27Which Idaho Falls-born lawyer was elected to the U.S. Senate in 1998 after three terms in the House?
Mike Crapo
Mike Crapo practised law in his home city through the 1980s and led the Idaho Senate before he went to Washington.
Q 28Which Idaho Falls-born journalist moderated the 2012 debate between Joe Biden and Paul Ryan?
Martha Raddatz
Martha Raddatz, a foreign affairs correspondent for ABC News, went on to co-moderate a 2016 presidential debate with Anderson Cooper.
Q 29Idaho Falls native Greg Carr set out to restore Gorongosa National Park in which African country?
Mozambique
Mozambique had seen the park ravaged by civil war; Carr, who made his money selling voice mail systems to phone companies, has funded its recovery for decades.
Q 30Todd Pedersen, who grew up in Idaho Falls, founded which smart-home security company in Utah?
Vivint
Vivint started in 1999 as APX Alarm, built on door-to-door selling, and took its present name in 2011.