The Rocky Mountains took shape during a period of intense plate tectonic activity that formed much of the rugged landscape of the western United States. Three major mountain-building episodes reshaped the west from about 170 to 40 million years ago (Jurassic to Cenozoic Periods). read more
The rocky cores of the mountain ranges are, in most places, formed of pieces of continental crust that are over one billion years old. In the south, an older mountain range was formed 300 million years ago, then eroded away. The rocks of that older range were reformed into the Rocky Mountains. read more
The Rocky Mountains, also known as the Rockies, are a major mountain range in western North America. The Rocky Mountains stretch more than 3,000 miles (4,800 km) from the northernmost part of British Columbia, in western Canada, to New Mexico, in the Southwestern United States. read more
The Rocky Mountains were formed by plate tectonic activity during three separate events, which occurred more than 100 million years ago. The Rocky Mountains are located in the western part of the United States and stretch for 3,000 miles from Canada to Mexico. read more