L
- Leadville - Magic City
- Limon - The Hub City of the Plains
- Loveland
- Gateway to the Rockies
- The Sweetheart City
- Longmont - Leftmont/Longtucky
- Lyons - Double Gateway to the Rockies (or Double Gateway to Rocky Mountain National Park)
Read more about this topic: List Of City Nicknames In Colorado, Nicknames By City