City Nature Challenge

City Nature Challenge

April 26 – April 29

Get to know your neighbors – plants, animals and people. The 2024 City Nature Challenge (CNC) is a friendly global competition among cities to see who can document the most wildlife. Join the CNC and contribute to community science.

  • Make your observations between Friday, April 26 and Monday, April 29
  • Between April 30 to May 5, help us identify as many observations as possible within the project. 
  • Observations must be uploaded by May 5 to count towards our total observations for the CNC. 
  • Results announced on May 6.


Here’s how you can get involved in the Denver-Boulder Metro area:

Training Workshops

To be announced.

Join a Hike

To be announced.

Lead a Hike

Hike leaders will guide a group trek sometime between Friday, April 26 and Monday, April 29. They will help others document the natural world with iNaturalist. Anyone can be a hike leader – a parent with their kids, a friend with their neighbors or a professional naturalist with a team of community scientists. Locations could be alleyways or mountain vistas, as long as they fall within the Denver-Boulder boundaries.

Email us to connect to a training session and to sign up.

Fly Solo

All you need is a smartphone and the iNaturalist app. Any observations you take between Friday, April 26 and Monday, April 29 will count towards the project. You have up until Sunday, May 5 to identify as many observations as you can.


Próximamente preguntas frecuentes sobre City Nature Challenge.

What is the City Nature Challenge? 

The City Nature Challenge (CNC) is an international effort to document biodiversity by finding and documenting plants and wildlife across the globe. Cities are encouraging their community members to get outside and document the plants and animals in their region. The CNC is organized by the California Academy of Sciences and the Natural History Museum of Los Angeles County.

Further questions? Please email us.

Why should you participate?

There is nature all around us, even in our cities! Knowing what species are here and where they are helps us study and protect them, but the ONLY way to effectively do that is by working together (scientists, land managers, community members, you name it) to find and document nature in our area. By participating in the CNC, not only do you learn more about local nature, but you can also make our urban areas a better place – for you and other species!



Denver Audubon logo
Denver Parks and Recreation logo
High Line Canal Conservancy logo
City Nature Challenge organized by logo
2022 The Nature Conservancy logo

Sign up for our e-newsletters!