Further complicating the issue is the fact that the Sierra Nevada is not in Nevada! The crestline of the mountain range is in California. All of this would have been much easier if California had agreed to the language in Nevada's Organic (1861) and Enabling (1864) Acts. That would have made the land east from the crest of the Sierra a part of Nevada. Of course, California was not about to part with Lake Tahoe and part of its eastern border which now includes the communities of Susanville, Truckee, Tahoe City, South Lake Tahoe, and many others to the south.
So remember -- Sierra is
plural for mountains, and Nevada is not to be made plural, and you will
sound very wise!
Library of Congress