Winnetka is a village in Cook County, Illinois, United States, 16 miles north of downtown Chicago. The population was 12,475 as of the 2020 census. The village is one of the wealthiest places in the United States in terms of household income. It was the second-ranked Illinois community on Bloomberg's 2019 Richest Places Annual Index. According to the U.…Winnetka is a village in Cook County, Illinois, United States, 16 miles north of downtown Chicago. The population was 12,475 as of the 2020 census. The village is one of the wealthiest places in the United States in terms of household income. It was the second-ranked Illinois community on Bloomberg's 2019 Richest Places Annual Index. According to the U.S. Census Bureau, Winnetka's median household income exceeded $250,000 in 2022.