Roxborough State Park captivates visitors with its prominent Fountain Formation: a breathtaking display of tilted red sandstone that originated over 300 million years ago from the gradual erosion of the Ancestral Rocky Mountains. Standing at a sixty-degree angle, this geological masterpiece represents millions of years of uplift and erosion, exposing rock formations from the Precambrian to Late Mesozoic. At Roxborough, visitors can see the transition between sedimentary rocks of the Great Plains and the crystalline basement rock of the Rocky Mountains, showcasing billions of years of Front Range geology.

The geological narrative of Roxborough unfolds nearly two billion years ago when ancient sediments transformed into metamorphic rock due to immense heat and pressure from tectonic plate collisions. The park's oldest rocks, the Precambrian crystalline rocks of the Idaho Springs Gneiss and Pikes Peak Granite, emerged 1.7 and 1.2 billion years ago, respectively. The Great Unconformity, a billion-year gap in the rock record, hints at a period of erosion. Around 300 million years ago, the Ancestral Rocky Mountains formed, eroding into sedimentary rocks that later became the oldest layers in the park. Over the next 65 million years, various climate and geologic changes shaped Roxborough's landscape, contributing to its unique rock formations and diverse ecosystems.

The geological formations at Roxborough include the Precambrian Basement Rocks, the Fountain Formation (300 Ma) with its striking red spires, the Lyons Formation (280 Ma) formed in an ancient desert, the Lykins Formation (250 Ma) representing a harsh tidal flat and the Morrison Formation (150 Ma) deposited during the Jurassic Period. The Dakota Group or Dakota Hogback (100 Ma) is primarily composed of beach and near shore sediments laid down on the west shoreline of a seaway that began to flood the center of the North American Continent around 100 million years ago. Finally, the Pierre Shale (70 Ma) reflects an inundation of the area by a shallow sea. Each formation tells a story of continual change, from mountain-building events and climate shifts to the traces of ancient life.

Roxborough State Park provides a glimpse into the ever-changing landscape of Colorado and the Rocky Mountain Region, earning recognition as a distinguished Colorado Natural Area, National Cultural District, National Natural Landmark and Leave No Trace Gold Standard Designated Site. Its geological wonders, combined with its biological diversity, make Roxborough a great destination for those eager to explore the geological history and natural beauty of the region.