Among all children under 18 years in the U.S., 43 percent live in low-income families and 21 percent--approximately one in five--lives in a poor family. This means that children are overrepresented among our nation's poor; they represent 23 percent of the population but comprise 33 percent of all people in poverty. Many more children live in families with incomes just above the poverty threshold. Young children under age 6 years appear to be particularly vulnerable, with 45 percent living in low-income and 23 percent living in poor families. Parental education and employment, race/ethnicity, and other factors are associated with children's experience of economic insecurity. This fact sheet describes the demographic, socioeconomic, and geographic characteristics of young children and their parents. It highlights important factors that appear to distinguish low-income and poor children in this age group from their less disadvantaged counterparts.