Public health and policy planning for adults with intellectual and developmental disabilities (IDD) is imperiled by the lack of ongoing national surveillance data on prevalence and health status. In 2018, the Administration on Intellectual and Developmental Disabilities appointed a workgroup of representatives from key federal agencies and national experts to recommend strategies to improve prevalence estimates and health surveillance for people with IDD. This article presents the workgroup findings on the availability of prevalence and health surveillance data for adults with IDD and suggested items that could identify respondents with IDD on national surveys with special attention to modifications in the National Health Interview Survey. We identify core constructs that must be measured to identify sample members with IDD in population surveys, and additional constructs which, if measured, would support more comprehensive identification of sample members and enhance ongoing surveillance of the health status, outcomes, and unmet needs of this population. We conclude with a brief review of methodological considerations to improve IDD national surveillance including cultural and linguistic sensitivity and the inclusion of U.S. territories in national surveillance protocols.