​Health care coverage varies widely among California’s 80 Assembly and 40 Senate districts. This report provides estimates of uninsured rates for children, nonelderly adults, and elderly persons, as well as for nonelderly persons overall, in all California Assembly and Senate districts — information that has never before been available. The estimates of uninsurance in Assembly and Senate districts were developed using data from a variety of sources and a method called “small area estimation” (described in the Appendix). As with all estimates, the estimates in this report vary in the precision with which they represent the “true” estimate. The California Health Interview Survey (CHIS), now underway at the UCLA Center for Health Policy Research, will greatly enhance the quality of the estimates that can be made for local areas.