Always Coming Home by Ursula K. Le Guin is a feat of world building. The book describe a future civilization in the Napa Valley of California called the Kesh. Set many centuries after an environmental catastrophe, the landscape and human genetics of the world still bear damage. There's an inland sea covering the Central Valley. The life expectancy is short; birth defects are common. Interestingly, there's a self-sustaining AI computer system remaining that's mostly ignored. The Kesh are a simple, matriarchal, agrarian people with elaborate rituals that evoke Native American archetypes and practices.
"Novel" is probably the wrong term for the text. It's a huge collection of narrative, poetry, songs, "researched" descriptions, charts, maps, interviews, and myths. It's the most comprehensive fictional world I've ever encountered, and since it's Le Guin, it leans heavily on anthropology. She concocted a whole language, cosmology, and social hierarchy. It's a rich, copious read. I'll admit that while Le Guin is a master writer, I skimmed the poetry after a while and ignored most of the glossary. I admire the effort behind Always Coming Home, and there was a lot to enjoy, but after 500 pages, I didn't feel the need to read every word.