| Boulder to Kinston (North Carolina) | 1,541.64 mi (2,481.02 km) |
| Boulder to Kirkland (Washington) | 993.88 mi (1,599.49 km) |
| Boulder to Kirksville (Missouri) | 669.43 mi (1,077.34 km) |
| Boulder to Kirkwood (Missouri) | 798.33 mi (1,284.79 km) |
| Boulder to Kiryas Joel (New York) | 1,622.56 mi (2,611.26 km) |
| Boulder to Kissimmee (Florida) | 1,577.55 mi (2,538.82 km) |
| Boulder to Klamath Falls (Oregon) | 871.82 mi (1,403.06 km) |
| Boulder to Knightdale (North Carolina) | 1,481.73 mi (2,384.62 km) |
| Boulder to Knik-Fairview (Alaska) | 2,368.18 mi (3,811.22 km) |
| Boulder to Knoxville (Tennessee) | 1,190.12 mi (1,915.32 km) |
| Boulder to Kokomo (Indiana) | 1,007.09 mi (1,620.76 km) |
| Boulder to Kuna (Idaho) | 621.44 mi (1,000.12 km) |
| Boulder to Kyle (Texas) | 808.12 mi (1,300.54 km) |
| Boulder to La Cañada Flintridge (California) | 817.52 mi (1,315.67 km) |
| Boulder to La Crescenta-Montrose (California) | 818.35 mi (1,317.00 km) |
