City Nature Challenge

Please note: Be sure to keep an eye on this page for updates on the status of the event as well as news about local events that may be scheduled during this global four-day event. This event usually occurs end of April – beginning of May each year.

What is City Nature Challenge?

City Nature Challenge is a worldwide citizen science endeavor getting people all over the world to observe the natural world around them and record what they find using the iNaturalist app. City Nature Challenge is an approved service project for PA Master Naturalist volunteers.

Take the City Nature Challenge!

Join Pennsylvania Master Naturalist and others in a fun challenge to see which city can document the most species. It is easy to participate by joining an event or making observations on your own using iNaturalist — sign up on and download the App for your device: iNaturalist for iOS and iNaturalist for Android. This year, more people than ever will get to join the fun and learning.

What to do?

With the iNaturalist App, you just take a picture of a plant or animal and the community will help identify what species it is. You can also photograph species on your camera and upload to the iNaturalist website later that day.

Any plant or animal observation made during the four days of the event in the Greater Philadelphia region and Pittsburgh and its surrounding counties will count towards the challenge.

You can participate by exploring the life in your backyard, in your local park or on a field trip with Master Naturalists from your chapter.

Not only is this a competition between metropolitan areas of Pennsylvania, cities across the world are participating — let’s show them what we’ve got!

To find out if your county is involved please click the city area nearest to you and click on link below. Be sure to check out the City Nature Challenge Website to see the list of global participants.

In preparation, sign up for iNaturalist.

Pennsylvania Master Naturalists are invited to join our statewide project. Time in the field making observations through PMN iNaturalist Project and City Nature Challenge qualifies for service. This is a private group and PMN staff will need your iNaturalist username to invite you to join.

City Nature Challenge – a PMN Service Project Webinar:

View the PA Master Naturalist CNC 2021 Report