Fowler lost his lead with three straight bogeys on the back nine.
Paul Casey is one of the joint leaders after an up and down round of one under par, he took an eight on the par-5 14, but bounced back brilliantly with 5 birdies in his last 11 holes to save his round. It's hard to make a lot of birdies for me around here.
Day admitted the course lay-out had played on his mind in both his rounds.
Health officials say E. coli bacteria have been found in a drinking water station at Erin Hills golf course where the U.S. Open is underway, but there have been no reports of illness.
It is going to be a surprisingly quiet weekend for defending champion and world No. 1 Dustin Johnson, as well as Nos.
The four-way tie was the most after two rounds in a U.S. Open since Winged Foot in 1974, back when the names were more familiar for a major - Raymond Floyd, Arnold Palmer, Gary Player and Hale Irwin, who went on to win his first major. After all, the U.S. Open has a lengthy history of getting the last laugh and this championship is only at the halfway mark. His game showed some rust at Erin Hills, especially off the tee on Thursday, when the last time he hit a fairway was on the 10th hole. The Japanese star began the day at 2-over par and is now 5-under and just two shots back of the lead.
Trump blasts court for ruling against travel ban at "dangerous time"
But the 4th Circuit was only ruling on the portion of the law restricting travel from the six countries for 90 days. The high court could still act before then on the separate emergency request in a similar case from Maryland.
"I was teeing off and I looked up and saw it on fire, and I felt sick to my stomach", American Jamie Lovemark said.
"I prefer a golf course where we can make some birdies, for sure", Casey added after a record-setting first round that featured 44 scores under par, shattering the previous record 39.
Aided by favourable morning conditions, the 28-year-old started on fire with three birdies in his first five holes and maintained that momentum to sign for a bogey-free seven-under-par 65.
That was three shots behind Fowler and fellow American Xander Schauffele, the 23-year-old having birdied the fifth to claim a share of the lead on his major championship debut. "But I think at the end of the day, it's competitive rounds and get the card in my hand".
McIlroy and Jason Day never recovered from theirs.
Who will survive the toughest test of the... But I couldn't have shot any higher.
In his last 17 starts in majors, No. 1 Johnson has eight top 10s, including his win at Oakmont a year ago, and just two missed cuts.
"In my good seasons, yes, but there have been times when I struggled, but had I taken the 8 14 years ago I probably would not have managed to get back like I did today", he said.