Las Vegas Strip is a stretch of
Las Vegas Boulevard in
Clark County, Nevada, immediately south of the
City of Las Vegas. The Strip is known for its concentration of casinos and resort hotels, including the 43-story
Mandalay Bay southwest of its intersection with Mandalay Bay Road, in the
unincorporated town of
Las Vegas Village is located diagonally across the intersection to the northeast; the 15-acre (6.1-hectare)
lot is used for outdoor performances.
 The annual
Route 91 Harvest
country music festival has been held there since 2014; the 2017 festival ran from September 29 to October 1.
Paddock may have considered attacking other outdoor concerts. He reserved a room that overlooked the August 2017
Lollapalooza festival in Chicago, but did not use it. He appears to have stayed in
Downtown Las Vegas from September 14 until the night of the shooting. Between September 22 and 24, he rented rooms at
The Ogden, which overlooked the open-air
Life Is Beautiful festival.
Paddock arrived at the Mandalay Bay on September 25, 2017, and the hotel booked him into a
complimentary room, because he was a frequent gambler at the casino.
 Three days later, he moved to the 32nd floor suite, which overlooks Las Vegas Village.
[b] He placed a
"Do not disturb" sign on the door, organized the room, and stockpiled an arsenal of weapons.
 Clark County Sheriff
Joe Lombardo said Paddock carried more than ten suitcases into his hotel suite during his preparation for the shooting.
Animation of a bump fire stock, showing how the trigger (red) is pulled by the trigger finger when the receiver is moved forward. It is reset when the receiver moves back due to
Twenty-three firearms, a large quantity of ammunition, and numerous
magazines capable of holding up to 100 rounds apiece were found in the suite.
 The firearms included four
DDM4 rifles, three
FN-15 rifles, one
AR-15 rifle with forward front grip, one .308-caliber
AR-10 rifle, one
Kalashnikov, and at least one made-to-order
LMT rifle and one handgun.
 Two of the rifles were equipped with
telescopic sights and mounted on bipods.
 Twelve of the guns were fitted with
bump fire stocks,
 which allowed for
recoil to actuate their triggers at a rate of 90 rounds in 10 seconds.
Bureau of Alcohol, Tobacco, Firearms and Explosives determined that the firearms found in his hotel room, along with more guns found in his homes, had been legally purchased in the states of Nevada, California,
 In the month preceding the shooting, he had attempted to purchase a large quantity of
tracer ammunition, but the gun dealer he approached did not have the item in stock.
Investigators found hidden surveillance cameras that were placed inside and outside the hotel room, presumably so Paddock could monitor the arrival of others.
 The cameras were not in record mode.
 Police said a handwritten note found in the room indicated Paddock had been calculating the distance, wind, and trajectory from his 32nd floor hotel suite to the concertgoers he was targeting on the festival lot.
At a press conference on October 4, Sheriff Lombardo stated there was evidence—which he declined to discuss—that Paddock intended to escape the scene, and that he may have had assistance from an accomplice.
 Investigators searched Paddock's room and found a "
bulletproof vest" and
breathing apparatus, which were survival gear that Paddock never used.
During subsequent investigations,
ammonium nitrate, which is often used in
improvised explosive devices, was found in the trunk of his
Hyundai Tucson SUV, along with 1,600 rounds of ammunition and 50 pounds (23 kg) of
binary explosive used to make explosive targets for gun ranges.
 Undersheriff Kevin McMahill said that while Paddock had "nefarious intent" with the material, he did not appear to have assembled an explosive device.