Spectators and players at Erin Hills watched as the airship collapsed and sank to the ground not far from the course at about 11:15 a.m. CDT on a sunny, breezy Thursday.
The Washington County Sheriff's Office said in a press release
the pilot -- the sole occupant -- had been taken to hospital with "serious burns and injuries."
No-one else was injured in the incident.
"The initial investigation reveals the blimp may have experienced mechanical problems prior to the crash," added the statement, saying earlier checks with the Federal Aviation Authority had deemed the aircraft was "lawfully operating at the proper altitude."
The blimp, which was not affiliated to the tournament or its broadcasters, was operated by AirSign, a national aerial advertising firm.
"Our thoughts and prayers are with the pilot at this time," said tournament organizer the United States Golf Association (USGA) in a statement.
US Open competitor Jamie Lovemark said he was about to drive on the fifth hole when he saw the blimp in trouble.
" I was teeing off and I looked up and saw it on fire, and I felt sick to my stomach," he told reporters. "I had the shakes. I felt terrible for the people inside. It was horrible."
AirSign later tweeted
: "Thanks to everyone for your concerns, the blimp pilot is being taken to the hospital but is expected to be OK. No details on cause of crash."
Fowler leads the way
The Erin Hills course -- at 7,741 yards the longest in US Open history -- was expected to prove a severe test, but world No. 9 Rickie Fowler scorched into the first-round lead with a stunning seven-under 65.
The 28-year-old, who is still chasing a first major title, ended the day one shot clear of England's Paul Casey and American qualifier Xander Schauffelle and two ahead of Americans Brian Harman and Brooks Koepka and Englishman Tommy Fleetwood.
"It was nice. You don't get many rounds at the US Open that are stress-free," said Fowler, who won the last of his four PGA Tour titles at the Honda Classic in February.
Defending champion Dustin Johnson, whose fiancee Paulina Gretzky gave birth to the couple's second child -- named River Jones Johnson -- Monday, found it more of a struggle and finished with a three-over 75.
The world No. 1, who defied a rules controversy
to win his first major in the US Open at Oakmont last year, missed the Masters at Augusta
after falling down stairs in his rental house on the eve of the tournament.
"I'm a little frustrated that I shot three over," Johnson told reporters. "I didn't play that bad. I just didn't putt very good."
The last player to win back-to-back US Opens was Curtis Strange in 1989.
World No. 2 Rory McIlroy visited parts of Erin Hills he would rather not have in a six-over 78 and was left to rue comments he made in the build-up when he dismissed criticism of the course's long rough.
Several players posted videos on social media mocking the waist-high grass along several holes, but McIlroy, back after five weeks out with a rib injury, said the fairways were ample, adding "if we can't hit within that avenue, you might as well pack your bags and go home."
Masters champion Sergio Garcia signed for a two-under 70, while Justin Rose, the man he beat in a playoff at Augusta, three-putted the last for a 72.
Jordan Spieth, the 2015 Masters and US Open champion, carded a one-over 73, while former world No. 1 Jason Day took 79.
Five-time major champion Phil Mickelson pulled out on the morning of the event to attend the graduation ceremony of his daughter, Amanda.
The 46-year-old left-hander, who would have flown over from California if the start had been delayed by bad weather, has been runner-up in the US Open a record six times and needs the title to become only the sixth ever player to win all four of golf's four major tournaments.
Erin Hills, located 35 miles northwest of Milwaukee in the Kettle Moraine region, was first opened in 2006 and is hosting its first US Open in something of a gamble for the USGA.
The body was under pressure to host a successful tournament following the farcical final round last year when Johnson was eventually penalised for moving his ball on a green, and for the poor condition of the Chambers Bay course the year before.
After Kevin Na and Lee Westwood, among others, highlighted the length of the rough, groundstaff subsequently cut the grass on four holes, but the USGA said the decision was "based on weather" and not player feedback.
The previous longest course for a US Open was the 7,695 yards of Chambers Bay during the second round in 2015.
The USGA accepted 9,485 entries, the fifth-highest total in US Open history, for the first stage of qualifying, whittled down a to a championship field of 156. The record of 10,127 entries was set in 2014.