As part of the 1996 Welfare Reform Act, the Census Bureau is required to determine how many grandparents are serving as caregivers to a grandchild. Using data from the Census 2000 Supplementary Survey, this paper presents demographic information on two types of grandparent households, and outlines the challenges associated with use of the new questions about grandparent care developed by the Census Bureau. We compare skipped-generation households, in which a grandparent and grandchild coreside but no parent is present, to three-generation shared-care households in which the grandparent claims primary responsibility for the grandchild. We focus on two geographic regions of the United States, New England and the Deep South, providing the first report on the prevalence and characteristics of these households, and the extent to which these attributes are geographically variable. We estimate that the population of three-generation shared-care families is at least as large as the population ofskipped-generation grandparent care families.We identify a number of differences between skipped-generation and shared-care households, especially with respect to the age of the grandchildren involved and the levels of economic hardship. Significant regional differences are also observed, with grandparent care households of both types being more common in the Deep South than in New England. We conclude that data using these new questions have the potential to greatly enrich our demographic understanding of grandparent households by shedding new light on a type of grandparent care often hidden from analysis: grandparents who are responsible for grandchildren in three-generation households.