The gross sediments of the Denver basin from Cambrian through Tertiary are discussed. Isopachous maps are presented. From these tectonic history of the Denver basin is reviewed and its structural development is reconstructed. The Denver basin is a result of numerous tectonic adjustments, both orogenic and epeirogenic, merged through time to form the present structural basin. The history from Cambrian to Recent represents a nearly complete cycle of tectonic evolution. In the course of this evolution Early Paleozoic troughs became Late Paleozoic mountain ranges and Early Paleozoic positives gradually subsided to retain marine sediments. Late Paleozoic troughs became post-Cretaceous mountain ranges and Late Paleozoic mountain ranges became Tertiary and Recent plateaus and sh llow basins. The Early Paleozoic positives, Siouxia and Sierra Grande, with possibly associated pre-Cambrian mountain ranges, completely subsided and became Tertiary basins.