Nationwide, about 8.8 million immigrants are eligible to naturalize but have not yet done so. Less than 10 percent of this group naturalizes per year. This report quantifies the economic benefits of naturalization to those eligible immigrants and the cities where they live and presents the first published estimates of the effect of naturalization on expenditures for public benefits. We examine naturalization-eligible immigrants in 21 cities, including cities both large and small, historic immigrant gateways as well as new immigrant destinations, and all 18 of the Cities for Citizenship coalition as of August 2015. Using econometric and microsimulation models, we are able to make important new findings of the benefits of naturalization for those eligible to naturalize and about the effects of increased naturalization on the communities where they live.