While the quality of health care has a powerful influence on the well-being of infants and children, little information is available about the medical services received by children. This section of the Dartmouth Atlas web site examines small area variations in children's health care in one region of the United States—Northern New England—where the state legislatures of Maine, New Hampshire, and Vermont now require routine reporting of medical claims from commercial insurance plans. All three states offer these data, along with Medicaid claims, for research and public reporting. Using these data, the Dartmouth Atlas now offers the first data showing the patterns of care received by nearly the entire population of infants and children for ambulatory physician services, hospitalization, common surgery, imaging, and outpatient prescription fills. Most importantly, we present these measures by hospital service areas and pediatric surgical areas, revealing the care provided by specific hospitals and their medical staffs. The findings show marked variation in care across the region. While there are many examples of excellent care, the findings raise troubling questions about whether the medical practice patterns reflect the care that infants and children need and that their families want.