This volume represents the fourth in a series of five Class I Overview histories prepared by the Colorado State Office, Bureau of Land Management. The purpose of these works is to develop a synthetic history of a given area in order to provide our managers and staff specialists with a baseline overview of the history in a district. We have prepared these documents district by district, and they are regularly used by BLM personnel for orientation, training, and literature searches by professional consultants. In addition, these Class I's are basic to the operation of BLM's Cultural Resource Management Program, because they provide the background that is required for field examination and evaluation of historic properties located on Bureau lands in Colorado. The overview is also used for the preparation of Resource Management Plans and Environmental Impact Statements. This work is the first time an author has attempted to write a broad view of northeastern Colorado, covering the area from the Continental Divide to Kansas and from Wyoming south to near Colorado Springs. This massive region represents a quarter of Colorado and contains the vast majority of Colorado's historic sites and events. That Steve Mehls was able to cover this huge area, within very strict page limits is a testament to his ability to abstract the important events in our history. It must be noted that the major cities, like Denver, Colorado Springs, Boulder, Fort Collins, and Greeley are only mentioned. This is because there is no public land in these places and the Bureau's mandate is to manage the public lands, not private estate. Therefore, some of northeastern Colorado's history is briefly noted, with the emphasis placed on the interaction between the Federal Government and its role in the settlement of the West.