Las Vegas Strip is a stretch of
Las Vegas Boulevard immediately south of the city of
Las Vegas in
Clark County, Nevada. 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, a 15-acre (6.1-hectare)
lot used for outdoor performances, is located diagonally across the intersection to the northeast.
 From 2014 onward, the venue hosted the annual
Route 91 Harvest
country music festival. The 2017 festival ran from September 29 to October 1,
[a] with over 22,000 attendees on the final day.
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.
 He also researched other large-scale venues in cities like
Boston as far back as May 2017.
Paddock arrived at the Mandalay Bay on September 25, 2017; he was booked into Room 32135, a
complimentary room on the 32nd floor, because he was a frequent gambler at the casino.
 Four days later, he checked into the neighboring suite of Room 32134, which was connected to Room 32135 via connecting doors. Both suites overlook Las Vegas Village.
[b] He placed a
"Do not disturb" sign on the door, organized the rooms, and stockpiled an arsenal of weapons there between September 25 and October 1, the day of the shooting.
 Clark County Sheriff
Joe Lombardo said Paddock carried more than ten suitcases into his hotel suite during his preparation for the shooting.
 He interacted with Mandalay Bay employees more than ten times during his stay, including two on the day of the shooting, though an
MGM Resorts International spokesperson said they were all "normal in nature".
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-four firearms, a large quantity of ammunition, and numerous
magazines capable of holding up to 100 rounds apiece were found in the suite.
 Fourteen of the firearms were
semi-automatic rifles: three manufactured by
Colt, two by
Daniel Defense, two by
FN Herstal, two by
LWRC International, two by
POF-USA, one with a
.223 Wylde chamber by Christensen Arms, one made-to-order by
LMT, and one by Noveske. The others were seven
AR-10-type rifles, one .308-caliber
bolt-action rifle, and one
Smith & Wesson Model 342
 The AR-15 rifles were fitted with
vertical forward grips and
bump fire stocks,
 the latter of which allowed for
recoil to actuate their triggers at a rate of 90 rounds in 10 seconds.
 The AR-10 rifles were equipped with various
telescopic sights and mounted on bipods.
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.
 However, he at some point managed to purchase another large quantity of tracer ammunition from a private seller at a
Phoenix, Arizona gun show.
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 (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.