Tumbledown Trails in Verona had offered the special rate for playing nine holes with carts Wednesday and $19.11 for 18-hole rounds played on the anniversary, the Milwaukee Journal Sentinel reported Tuesday.
However, course General Manager Marc Watts apologized Tuesday after negative reactions to the promotion in the media and from the public.
"This is the first time we've had any negative comments," Watts said. "So many people have come in and said, 'What a unique way to put that out there so people don't forget.'
"We'll do something next year. I guarantee you it won't be this, but we will not give up and will not stop trying to remind people of 9/11."
The golf course's Facebook page said officials were considering closing the course Wednesday.
"We are now worried about what people will do/say to our staff & do not want anything to happen or get out of control. Sorry for the inconvenience this may have caused anyone," the post read.