Case File: Mini-Dinosaur Location: Cortez, Colorado Date: 1930s to present? Description: Cortez is municipality and county seat of Montezuma County, Colorado. The city population was 8,482 at the 2010 census. In 1886, the town was built to provide housing for the men working on the tunnels and irrigation ditches required to divert water out of the Dolores River and into Montezuma Valley. The town was named for Spanish conquistador Hernando Cortez.