"This is quite a phenomenon," said Bruce Small, who went to see the disk while visiting from Raymond.
The disk is 300 feet wide and completely frozen. It has drawn onlookers from all across Cumberland County.
"I wanted to see it for myself and take a few pictures," Small said.
Ruth Starke, who works in Westbrook, also stopped by.
"It's just interesting because it's not something that people see every day. It's not normal to see a giant floating disk in the water," she said.
Cam Gordon, who also works in Westbrook, said it was "nice to see the seagulls are having a nice ride and the ducks, too."
Westbrook city officials say the disk formed from the churning water current created by the waterfall just a hundred feet north of the disk that is causing it to slowly spin counterclockwise.
Pictures and videos of the naturally occurring phenomenon have reached as far as South Africa.
"I was texting my husband this morning. He's in Cape Town and he asked me if I was going to take the kids to see the spinning ice disk in Westbrook and I said, 'What is that?'" said Portland resident Amy Barker.
Locals and Westbrook city officials say the disk of ice is a welcome sight to see along the river.
City officials said the disk will probably stick around for a few days until the weather causes it to melt or the river freezes up.