Police believe multiple shooters may have been involved, with all suspects so far unknown and still at large.
The students were shot at Nome Park, just north of Aurora Central High School, where officials set up a secure perimeter and classes were closed for the day.
An earlier post from Aurora Police on Twitter mistakenly said the school had gone into lockdown.
All six teenagers were students at Central High School, which had more than 2000 students as of 2019, according to the National Centre for Education Statistics.
Aurora Police Chief Vanessa Wilson said the injuries suffered by the six teens were non-life-threatening.
Chief Wilson said one of the victims had a tourniquet applied to their wound by a school staffer and underwent emergency surgery at the hospital.
Children’s Hospital confirmed three of the six teens were treated at their facility, and that all three were in a stable condition.
Chief Wilson said several rounds from different calibre weapons were collected from the scene, indicating it was likely that multiple suspects in vehicles and on foot were involved.
No arrests have been made.
The city of Aurora’s website says Nome Park is 0.8 acres and features a playground and community garden.