An extensive and very useful bibliography for United States Environmental History has been compiled by the College of Natural Resources at the University of California at Berkeley.  The bibliography is organized topically for easier reference.  Most of the works are secondary, but some primary sources are listed as well.  Some of the material was written specifically as environmental history and the rest can be gleaned for insights that can be adapted by the reader for use in new works of environmental history.  


The Library of Congress has produced its first digital collection of archival material and made it available to the public as "California As I Saw It." The collection includes the full text and illustrations of "First Person Narratives" of California history from 1849 to 1900.  This is a very important compilation of primary sources covering the first half century of statehood beginning with the Gold Rush.  Since these materials were culled from the Rare Books and Special Collections of the Library of Congress, they are not readily available to students in other forms.  


Another excellent digital collection from the Library of Congress covers the history of the American conservation movement from 1850 to 1920.  The archived documents are pertinent to all three of the fields which this student guide addresses -- environmental, California and Western U.S. history.  Although too numerous to list here, the Library of Congress holdings include proceedings from the 1st National Conservation Congress of 1909, from the debates surrounding the California Forest Reservations and Parks Act which created Yosemite Park, and text from the American Antiquities Act under which William Kent bequeathed Muir Woods to the United States.  


The University of Kansas provides on-line access to the "Kansas Collection."  This collection comprises excellent and mostly primary sources on Kansas, Great Plains and Western U.S. history from the mid-19th century onward.  Materials include documents pertaining to the westward overland journey via the Santa Fe trail and on other subjects such as ranching and the economy of the Plains.  


During the quarter century that began with the Civil War, the government of the United States encouraged migration to the West through a series of land allocation programs.  The most famous of these, and the model for those that followed, was the Homestead Act of 1862, which took effect on the same day as President Lincoln's Emancipation Proclamation.  While land allotments were primarily designed to generate economic growth and build political bonds between the citizenry and the nation, they were intimately tied to federal Indian policy as well.  One of the principal efforts to reshape Native American life in the West was the Dawes Severalty Act of 1887.  


In 1893, American historian Frederick Jackson Turner wrote a ground-breaking analysis of the unique role of the Western frontier in shaping the history of the United States and the character of the American people.  Although many of Turner's conclusions are challenged today, his pioneering work set the stage for the field of Western U.S. history.  Students of the American West cannot escape consideration of Turner's Frontier Thesis, available here in full text.


Native American history in the West is often difficult to study from the perspective of indigenous populations on account of limited source material.  Native American/Euro-American interactions are easier to study but the documents left to us by the latter group must be understood in the context of a relationship of dominance and subordination.  Even progressive citizens in the 19th century accepted a priori the notion of Native cultural inferiority.  One such progressive was Alice Fletcher (1838-1923), whose anthropological study of the Sioux, and particularly of Sioux women, was a pioneering work for its time.  Camping with the Sioux (1881) is an invaluable document for understanding the course of "Indian policy" and is among the holdings of the Smithsonian Institution's National Anthropological Archives.


Photographs can often provide useful insights into the conditions of the past.  Over 30,000 images of the American West during the period 1860 to1920 are available through the Western History and Genealogy Department of the Denver Public Library.  The photos include images of Colorado and Western landscape, miners and the mining industry, Native Americans and more.  


The advent of the Franklin Roosevelt administration during the Great Depression of the 1930s produced a far-reaching federal response to the nation's economic problems.  FDR's New Deal sought to restore prosperity in part by adopting a systematic approach to natural resource management that had a major impact on the trans-Mississippi West in particular.  The New Deal document library of Columbia University houses a wealth of materials that illustrate the intersection of Western U.S., environmental, and New Deal history.  Recommended documents include: 

FDR's Campaign Address on Public Utilities and Hydroelectric Power, Portland, Oregon, September 21, 1932.

FDR's Message to Congress on the Use of Our National Resources, January 24, 1935.

Report of the Great Plains Drought Area Committee, August 27, 1936. 

FDR's Address at Bonneville Dam, Oregon, September 28, 1937.

FDR's Address at Timberline Lodge, Oregon, September 28, 1937.

My Hopes for the CCC, Robert Fechner, Director, Civilian Conservation Corps, January 1939. 


The Museum of the City of San Francisco offers a series of on-line exhibits relating to the city's history as well as to matters of relatively contemporary relevance.  Additionally, the museum's website provides a link to San Francisco history resources.  The history site is organized as a topical index for easy reference.  


For students interested in contemporary issues, especially environmental politics, legislation and regulation, the United States Environmental Protection Agency maintains a History Office which compiles data relevant to the agency's history.  Of particular utility are the finding aids for the History Office collections and oral history interviews.