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 became an international event!

2018 Results

68 cities took part

  • Buenos Aires, Argentina
  • La Plata City, Argentina
  • Campo Grande, Brazil
  • Curitiba, Brazil
  • Florianópolis, Brazil
  • Manaus, Brazil
  • Rio de Janeiro, Brazil
  • Salvador, Brazil
  • São Paulo, Brazil
  • Vancouver, Canada
  • Waterloo Region, Canada
  • Barcelona Metropolitan Area, Catalonia
  • Hong Kong SAR, China
  • Bogotá, D.C., Colombia
  • Prague, Czech Republic
  • Berlin, Germany
  • Ahmedabad, India
  • Mumbai, India
  • Padova, Italy
  • Rome, Italy
  • Tokyo, Japan
  • Klang Valley/Greater Kuala Lumpur, Malaysia
  • Hermosillo, Mexico
  • Monterrey - Zona Metropolitana, Mexico
  • Guimarães, Portugal
  • Cádiz, Spain
  • Madrid Metropolitan Area, Spain
  • Bristol & Bath City Region, United Kingdom
  • London, United Kingdom
  • Plymouth, United Kingdom
  • Amarillo Area, USA
  • Austin Area, USA
  • Baltimore, USA
  • Bangor, Lewiston & Portland, USA
  • Boston Area, USA
  • Boulder, USA
  • Charlottesville, USA
  • Chicago Wilderness Region, USA
  • Cleveland, USA
  • Dallas/Fort Worth Area, USA
  • Denver Metro Area, USA
  • Duluth and Surrounding Area (Twin Ports), USA
  • El Paso, USA
  • Greater Concord - Cabarrus County, USA
  • Houston Area, USA
  • Indianapolis, USA
  • Lake Charles/Southwest Louisiana, USA
  • Los Angeles County, USA
  • Lower Rio Grande Valley, USA
  • Maui, USA
  • Miami, USA
  • Minneapolis/St. Paul, USA
  • Nashville, USA
  • New York City, USA
  • Omaha Metro, USA
  • Palmer Station, Antarctica, USA
  • Pittsburgh, USA
  • Raleigh (Triangle Area), USA
  • Richmond, USA
  • San Antonio Area, USA
  • San Diego County, USA
  • San Francisco Bay Area, USA
  • Seattle Metropolitan Area, USA
  • Southern Oregon, USA
  • St. Louis City & MSA Region, USA
  • The Wasatch Front (Salt Lake City), USA
  • Tulsa Region, USA
  • Washington, D.C. Metro Area, USA

More than 17,000 people participated

Over 441,000 observations were made

18K species were found

599 rare / endangered / threatened species documented!


San Francisco swept all three categories with 41,737 observations, 3,211 species, and 1,532 participants.

For a complete list of 2018 results see the Leaderboard.

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!


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


Houston found the most species with 2,419


Los Angeles had the most participants with 1,034 (including 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