Jefferson County, aka JeffCo, is located along the Front Range of the Rocky Mountains, adjacent to Denver. As of 2010, the population was 534,543, making Jefferson the fourth-most populous county in Colorado. The county seat is Golden, and the most populous city is Lakewood.
Coors Brewing Company, based in Golden, is a major employer in Jefferson County and the largest single brewery in the world. The county is named for the third U.S. president, Thomas Jefferson. Outdoor recreation is plentiful and includes Pike National Forest, Lost Creek Wilderness, Rocky Flats National Wildlife Refuge, and Two Ponds National Wildlife Refuge.
Visit the Jefferson County Government website.

County Towns
- Arvada – part
- Applewood
- Aspen Park
- Bow Mar
- Buffalo Creek
- Columbine
- Conifer
- East Pleasant View
- Edgewater
- Evergreen
- Foxton
- Genesee
- Golden
- Idledale
- Indian Hills
- Ken Caryl
- Kittredge
- Lakeside
- Lakewood
- Littleton – part
- Morrison
- Mountain View
- Pine
- Pine Junction
- Superior – part
- West Pleasant View
- Westminster – part
- Wheat Ridge
Adjacent Counties
- Adams – east
- Arapahoe – east
- Boulder – north
- Broomfield – northeast
- Clear Creek – west
- Denver – east
- Douglas – east
- Gilpin – northwest
- Park – southwest
- Teller – south
Special Events
- Jun – Evergreen Rodeo
- Jul – Evergreen Summerfest
- Jul – Evergreen Jazz Festival
- Oct – Knock your Boots Off Chili Cook-Off & Beer Tasting in Golden
- Oct – National Fossil Day at Dinosaur Ridge in Morrison
- Nov – Evergreen Winterfest

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