The California State Library has several stereo views of Bidwell Mansion and Chico, designed to be viewed in a stereoscope. The photos depict right-eye and left-eye views of the same scene, and when viewed through the stereoscope appear three dimensional. Pretty cool for the 19th century, and a popular form of educational entertainment.
In 1870 Oliver Denny, a photographer with a studio in Marysville, did a series of stereo scenes, showing towns on the California Pacific Railroad. Two of the photos in the state library have his imprint, the one above, and another of Bidwell’s flour mill.
An even earlier view of Bidwell Mansion is the one below.
The state library attributes this picture to E.A. Kusel, a native of Germany who came to California during the Gold Rush. Around 1865 he established a photography studio in Oroville, where he also served as the district clerk of the Oroville school system. During 1868-69 he maintained a branch studio in Chico. This photograph of the Mansion was probably taken upon the mansion’s completion in 1868, making it the earliest photograph of Bidwell Mansion.
This one looks like it was taken at the same time, but we can’t be sure, since it is unattributed. But it has the same barren look to the surrounding landscape.
Information about Oliver Denny and E. A. Kusel come from Pioneer Photographers of the Far West: A Biographical Dictionary, 1840-1865, by Peter E. Palmquist and Thomas R. Kailbourn. You can view it online at Google Books.