Denver officials estimate a total of 300,000 people will be downtown Friday and Saturday evening for the holiday parade.
While police officials will not get into specifics about Homeland Security tactics following the recent mass shootings in San Bernardino, the presence of officers is noticeable.
"I can't say whether or not we're doing anything different than in past years, but I can tell you that we are monitoring and we will respond as necessary,” said Denver police spokeswoman Christine Downs.
"It's definitely a little scary coming up with big crowds," said Denver resident Desirae Samuelson. She is at the parade with her husband and children. "We wanted to have fun and enjoy the holiday. And we're not going to live in fear."
State officials tell Denver7 Homeland Security will likely be beefed up during the holidays.
"We'll have additional eyes on looking at any potential threats,” said Colorado Homeland Security director Kevin Klein.
"It's definitely in the back of our brains,” said Samuelson. “We're going to stay vigilant and keep our eyes open."