How it got Started

Started in 2016 for the first-ever Citizen Science Day, the citizen science teams at Natural History Museum of Los Angeles County and California Academy of Sciences dreamed up the City Nature Challenge as a fun way to capitalize on their home cities’ friendly rivalry and hold a citizen science event around urban biodiversity. The first City Nature Challenge was an eight-day competition between Los Angeles and San Francisco, engaging residents and visitors in documenting nature to better understand urban biodiversity. Over 20,000 observations were made by more than 1000 people in a one-week period, cataloging approximately 1600 species in each location, including new records for both areas. During the 2016 CNC, we heard so much excitement and interest from people in other cities that we decided we couldn’t keep to the fun just to ourselves. In 2017 the City Nature Challenge went national, and in 2018, the CNC is now an international event!

2017 Results

16 cities took part

  • Austin
  • Boston
  • Chicago
  • Dallas/Fort Worth
  • D.C.
  • Duluth
  • Houston
  • Los Angeles
  • Miami
  • Minneapolis/St. Paul
  • Nashville
  • New York
  • Raleigh
  • Salt Lake City
  • San Francisco
  • Seattle

More than 4,000 people participated

Over 125,000 observations were made

8,600 species were found

392 rare / endangered / threatened species documented!

most observations

Dallas/Fort Worth made the most observations with 23,957

most species

Houston found the most species with 2,419

most participants

Los Angeles had the most participants with 1,034 (includes people who submitted via social media)

2016 Results

2 cities took part, San Francisco versus Los Angeles

Over 1,000 people participated

* Over 19,800 observations were made

2,544 species were found

Los Angeles beat San Francisco! Here’s the breakdown

SF Bay Area


L.A. County