As cities continue to deal with the impacts of rapid urbanization and climate change, leaders are also working to make cities more sustainable.

Coworking Cafe recently conducted a study to determine the top U.S. green cities, and one Colorado city ranked particularly high on the list.

To determine the rankings, Coworking Cafe analyzed U.S. cities with at least 100,000 residents and compared 12 key sustainability-related metrics across five general categories (commute metrics, transportation infrastructure, environmental quality, sustainable energy and recycling, and green spaces and infrastructure). These data points touched on topics like air quality, green energy, bike/scooter share system, and more.

Denver ended up ranking 15th overall, with a total score of 38.97. According to the study, 1.9% of the population commutes to work by bike in Denver, and another 4.9% commute to work by public transportation.

The study does note that the Mile High City struggles with air quality, as its air quality index is 68. However, Denver has 992 green buildings and 353 charging stations, which “signal promising progress in clean energy adoption and sustainable urban development.”

San Francisco ranked as the top sustainable city in the U.S., with an overall score of 62.50.

Check out the full study results here.