The town is approximately 16 miles (26 km) northeast of Moab, near State Route 128.

The community, and the valley within which it is located, was named for castle-like rock formations near the town site.

[5] According to the United States Census Bureau, the town has a total area of 8.1 square miles (21 km2), all land.

In 2000, there were 230 housing units at an average density of 28.5 per square mile (11.0/km2).

36.1% of all households were made up of individuals, and 4.4% had someone living alone who was 65 years or older.