This document, which is designed to provide Iowa literacy service providers and funding agencies with information about the distribution of adult literacy proficiencies over various regions of Iowa, presents and discusses synthetic estimates of adult literacy proficiencies. First, the procedure that was used to develop synthetic literacy estimates for each of Iowa's 17 Public Use Microdata Areas (PUMAs) based on data from the 1990 Census and three literacy scales reported by the National Adult Literacy Survey is explained. Next, the accuracy of previously published statewide synthetic estimates is examined, and the synthetic estimates are compared to recent Iowa State Adult Literacy Survey results. The process of summarizing the synthetic estimates of the prose, document, and quantitative literacies of adults residing in each of Iowa's 17 PUMAs and the steps in calculating general estimates for clusters of PUMAs are outlined. Appended are a map of the geographical boundaries of Iowa's PUMAs and 17 tables reporting the synthetic estimates of the combined, prose, document, and quantitative literacy estimates of adults residing in each PUMA. (MN)