Research studies based on statistics for the United States as a whole have documented differences in child and family well-being between children in low-income families and children in more affluent families and between children in single-parent families and children in two-parent families. However, researchers have not explored differences in well-being in these families at the state level because of a lack of state-level data. The National Survey of Children's Health (NSCH) provides representative data at both the national and state levels on several important areas (or "domains") of parental and family functioning and well-being. Child Trends drew on these data for 2003 to analyze differences in well-being by family income and family structure in Maryland, thus illustrating the richness of this new source of statistical information. This "Research Brief" presents the authors' findings. Although they found that most children and their parents in Maryland are functioning well in most domains, "significant differences exist in many important measures of child and family well-being between children and their parents in low-income families and their counterparts in higher-income families". Similarly, "significant differences exist in many measures of child and family well-being between children and their parents in families headed by single mothers and families headed by two biological or adoptive parents". In particular, the often-substantial contrasts between low-income single-parent and higher-income two-parent families serve as a telling reminder of the difficulties faced by children in households with both of these family risk factors. (Contains 2 figures and 1 table.)