Denver earns its nickname honestly: one of the steps of the State Capitol is marked as exactly one mile above sea level, and from the city the Front Range of the Rocky Mountains fills the western horizon like a jagged wall. The city spreads across the high plains at the foot of the mountains, a big, sunny, sprawling place where the snowy peaks are visible from almost every street on a clear day.
It began as a gold rush town in 1858, when prospectors found traces of gold where Cherry Creek meets the South Platte River. The real riches came later, from silver, the railways and cattle, and the mining towns in the mountains, such as Georgetown, Idaho Springs and Central City, still show their Victorian origins. Today Denver is a busy modern city with good food, craft breweries and a lively centre around Union Station and the old Larimer Square.
The rides from here climb fast. Georgetown, an old silver mining town on Interstate 70, is the starting point for Guanella Pass, a scenic byway that rises above 11,000 feet before descending toward Grant. Golden Gate Canyon State Park lies just west of Golden, with winding roads through pine forest and meadows, and the road up Mount Evans, now officially renamed Mount Blue Sky, climbs to above 14,000 feet, one of the highest paved roads in North America. It has required timed-entry reservations in recent seasons, so check before you go.
Altitude changes everything. Bikes lose power as the air thins, riders tire faster and dehydrate easily, and the sun is fierce. In summer, afternoon thunderstorms build over the mountains with lightning and hail, so the golden rule is to be up high in the morning and down by early afternoon. The high passes may be closed from autumn to late spring, and snow can fall in any month above timberline. Interstate 70 into the mountains is heavily congested at weekends, especially on Sunday afternoons heading back to the city.
Denver has fuel, food and every service, and the suburbs to the west, around Lakewood and Golden, are good places to fill up before you head into the hills. Carry water and an extra layer: a hot day on the plains can be freezing at the top of the pass, and the weather can change within an hour.