NEW TNMCorps Mapping Challenge for City / Town Halls in CA & NV!

Release Date:

TNMCorps Mapping Challenges shift to the Pacific Coast with a new challenge for city/town halls in California and Nevada. Just in time to help fend off those winter blues, too!

As you can see from the map, much work has already been done in these states. However, there are several communities in the Los Angeles and San Francisco metropolitan areas that still need to be collected.

TNMCorps Mapping Challenge: City/Town Halls in CA & NV

(Public domain.)

Not sure what each point color means?   

These colors are part of our tiered editing process and signal to other editors that a point has passed through a specific tier.  

TNMCorps Point Border Colors

(Public domain.)

Our November 2018 newsletter has an article titled Editor Roles and Point Colors that describes this process further.  


Tips and tricks for this challenge:  

Local Government: Incorporated vs. Unincorporated 

  1. California has 482 municipalities which consist of cities and towns.   
  2. Nevada has far fewer municipalities with only 19 cities.  
  3. See the Cities vs. Towns vs. Villages article in our September 2019 newsletter for more information on the different types of governing bodies. 


Possible Sources 

  1. Remember to confirm each entry in a list with an authoritative source (e.g., the city or village’s website) before using it to update the map.   
  2. See the How to Spot an Authoritative (Re)Source article in our November 2017 newsletter for why this is important.   


  1. California’s state website contains a directory of local governments that lists both counties and cities along with websites.   
  2. The California State Association of Counties also contains a list of cities in each county, but no websites or addresses.  
  3. Here is Wikipedia’s list of cities and towns


  1. The League of Nebraska Municipalities maintains a list of member municipalities along with addresses and websites.  
  2. Wikipedia also contains separate lists of cities


Proper Point Placement 

Our November 2018 newsletter includes an article on aerial interpretation for city/town hall structures. This article walks you through how to identify which building to place a point on when examining aerial imagery. 


Interested in collecting city/town halls elsewhere? 

We’re collecting city/town halls nationally, so feel free to research these features throughout the U.S.  Other priority states include (in order of priority) Colorado, Iowa, and Indiana.  Note that only city/town halls in California and Nevada will count towards this challenge.   


If you have any questions during the mapping process, reach out to us at and we’ll will be happy to assist!  Thank you for all that you do, and happy mapping!