Eldorado Canyon State Park, Colorado state park in Boulder County, US

Eldorado Canyon State Park covers 885 acres in Boulder County, Colorado, with a developed Inner Canyon and undeveloped Crescent Meadows. A narrow gorge cuts between reddish-brown and grey rock walls; a dirt path with a low stone retaining wall runs along the base of the sheer right-hand face, and dark green trees grow in the crevices below.

Ute people lived within the canyon walls, which sheltered them from Colorado winters, before settlers arrived seeking gold and farmland. At the start of the twentieth century the community of Eldorado Springs grew into a resort with warm artesian springs and hotels such as the Crags Hotel, the Eldorado and the Grand View; the Crags Hotel burned in 1912. The state established the park in 1978, and it now covers 885 acres split between the Inner Canyon and Crescent Meadows.

The canyon's name comes from Eldorado Springs, the resort town established at its mouth around 1900, which drew Denver residents and celebrities to warm artesian springs and hotels such as the Crags Hotel, the Eldorado and the Grand View. The Crags Hotel burned in 1912. Between 1906 and 1949, Ivy Baldwin crossed the canyon on a tightrope 580 feet above the floor.

The park is open during daylight hours only; visitors must leave before dusk. Timed vehicle entry reservations are required on weekends and federal holidays from May 1 to October 1. The entrance is on State Highway 170 just west of Eldorado Springs. Snow and ice are common on roads and trails from mid-October through late April, and afternoon thunderstorms can arrive suddenly in summer.

Between 1906 and 1949, Ivy Baldwin crossed the canyon on a tightrope 580 feet (180 m) above the floor, a feat recalled today by climbers who scale the same walls on more than 1,000 technical routes. The park's rock faces near the visitors center are estimated at over 1.5 billion years old.