Yosemite National Park - California
There are thousands of public domain images available from the U.S. National Park Service that make great scenic view wallpaper. The images are available in high resolutions, which means they can be adjusted to fit your preferred screen resolution. I have chosen over 50 images from the archives, but there are hundreds more available from the NPS Digital Image Index.
The first image is from Yosemite National Park.
For the best results download the highest resolution image by left-clicking the small image above. In Windows, you right-click that large image and click the "Set as desktop background" menu item. The gallery was originally published in September 2010.
Photo credit to National Park Service