| Boulder to Yonkers (New York) | 1,641.64 mi (2,641.96 km) |
| Boulder to Yorba Linda (California) | 809.66 mi (1,303.03 km) |
| Boulder to York (Pennsylvania) | 1,503.16 mi (2,419.11 km) |
| Boulder to Yorktown (Indiana) | 1,041.12 mi (1,675.53 km) |
| Boulder to Yorkville (Illinois) | 884.02 mi (1,422.69 km) |
| Boulder to Youngstown (Ohio) | 1,289.42 mi (2,075.13 km) |
| Boulder to Youngsville (Louisiana) | 1,014.05 mi (1,631.95 km) |
| Boulder to Ypsilanti (Michigan) | 1,132.96 mi (1,823.33 km) |
| Boulder to Yuba City (California) | 873.51 mi (1,405.78 km) |
| Boulder to Yucaipa (California) | 769.89 mi (1,239.02 km) |
| Boulder to Yucca Valley (California) | 737.58 mi (1,187.02 km) |
| Boulder to Yukon (Oklahoma) | 513.62 mi (826.60 km) |
| Boulder to Yulee (Florida) | 1,478.08 mi (2,378.74 km) |
| Boulder to Yuma (Arizona) | 727.96 mi (1,171.54 km) |
| Boulder to Zachary (Louisiana) | 1,021.85 mi (1,644.51 km) |
