The walnut industry involves the cultivation, harvesting, processing, and distribution of walnuts, a popular tree nut known for its health benefits and culinary uses. Major producers include countries like the United States, China, and Iran, with California being the leading state in walnut production. Walnuts are rich in omega-3 fatty acids, antioxidants, and other nutrients, making them a sought-after ingredient in various food products. The industry also faces challenges such as climate change, pest management, and market fluctuations, which can impact supply and pricing.