Introduction: This study examined the geographic distribution of childhood lead poisoning screening activities in relation to the density of the population at risk of lead exposure in the home in the Île-de-France region for the periods 2004–2005 and 2011–2012. Methods: The data used were from the population census (INSEE), the housing stock of potentially substandard private housing (PPPI) built before 1949 (Filocom), and the National Surveillance System for Lead Levels in Minors (SNSPE) in the Île-de-France region. The data were mapped at the municipal level. Results: In 2011–2012, the departments of Paris and Seine-Saint-Denis accounted for 60% of children aged 1 to 6 living in PPPI housing built before 1949. These two departments carried out 70% to 80% of screening activities. A decrease of more than 50% in screening and surveillance activities for childhood lead poisoning was observed between the 2004–2005 and 2011–2012 periods. Discussion: The decline in screening and surveillance activities for childhood lead poisoning parallels the decline in screening yield. Lowering the threshold for defining childhood lead poisoning to 50 μg/L, effective since June 2015, could automatically increase screening yield and revitalize screening efforts. The significant geographic variation in screening activities would warrant a survey of relevant institutional and community leaders to identify the causes.