Drawing upon data derived from extensive written records as well as historical maps, this project investigates spatial patterns of residential segregation in Nineteenth Century American cities, exploring issues of wealth, occupation and race. More basically, every individual citizen, to the furthest extent possible, is mapped at his or her place of residence over the period of study in three major American cities. To accomplish this goal, the project team has developed a credible geospatial network, similar to the contemporary TIGER database, that covers Washington, D.C., Nashville, Tennessee in 1860 as well as Omaha, Nebraska for 1870. Address locator services were created based upon the historic street network, and census records represented as data points were matched with address information from city directories so they could be geocoded and adjusted to fit accurately to their true spatial locations. The research therefore has the effect of creating a resource for historical inquiry, and it enables immediate analysis of the study areas. When mapped, census records that contain information about personal estate values, real estate values, occupations and race provide quantitative spatial data about economic segregation and ethnic/racial segregation in three major American cities prior to the commercial introduction of the automobile.