About Afield Trails

Afield Trails was founded in 2016 in Louisville, Colorado, between Denver and Boulder. The guide for Rocky Mountain National Park is our first product. The app started as a daydream during hikes in the Rocky Mountains about what a modern guidebook should look like. We source our geographic data from publicly available local, state, and federal databases to build up-to-date maps of national park trail systems, plant communities, wildlife ranges, geology, and more!

Our Team

headshot of Patrick Lacz
Patrick Lacz
Founder & Software Engineer

Patrick Lacz is a lover of data, computers, and the outdoors. He spent many years as a software engineer at Google before starting Afield Trails. When not programming or hiking (what passes for work), he enjoys time with his family, rock climbing, and playing board games.

headshot of Aaron Sidder
Aaron Sidder

Aaron Sidder is an ecologist, science writer, and previous AAAS Mass Media Fellow at National Geographic. He previously worked at the U.S. Geological Survey and as a freelance science writer, with publications at National Geographic, Smithsonian Magazine, Eos, 5280 Magazine, and Ecosphere. Outside of work, you can find Aaron on his bike, playing the guitar, wrestling with his dog, or out on the town with his wife.


Our contributors are local experts — researchers, history buffs, and fantastic writers.

Dr. Katie Langin: Dr. Langin holds a PhD in ecology and currently works as a freelance writer in Fort Collins, Colorado. Her work has appeared in National Geographic, Science Magazine, Slate, and other publications.

Dr. Beth Simmons: Dr. Simmons is a noted historian and geologist who has authored innumerable books and articles about the geological and human history of the Front Range, plus produced two hour-long videos, all available at the Dinosaur Ridge Visitors Centers (Colorado).

Janet Chu: Janet taught high school biology for 38 years and has conducted butterfly population studies on Boulder County (Colorado) open space for 14 years, documenting nearly 200 species. Since 1983 she has organized the annual Fourth of July butterfly count at the Cal-Wood Education Center in western Boulder County. She is co-author of “Butterflies of the Colorado Front Range”.

If you have an interest in being a contributor, please contact us at info@afieldtrails.com.