"It blew me away," said one visitor. "This is my sixth trip here. This is scary," he added while pointing out the long lines.
The crowds stretched for hundreds of feet. The first line being the one just to get into the parking lot.
"We are overcrowded," said a park worker.
The Zion National Park Twitter account has been tweeting out messages all weekend to warn drivers where and where not to park.
"A bus runs every four minutes," the employee said of the shuttle from the parking lot to the park's entrance. "Each bus holds 68 people, and we're literally having people wait almost an hour. That's a lot of people in line."
"It's Labor Day weekend," said another parkgoer. "It's a National Park and it's the 100th year anniversary of the National Park Service. So, if they don't get a crowd now, they'll never get a crowd."