The depiction of a historical-period property on an early map, whether a house, a ranch, a mining prospect, or an irrigation canal, is often the earliest (and sometimes the only) evidence that cultural features once existed in a particular place. Statistical Research used early maps as a regional preservation-planning tool by systematically examining a group of early maps of the county for depictions of cultural features. The typology will be used to plot the sites, distinguished by type, on a single map (or possibly on a series of maps) to be digitized by Pima County and incorporated into its GIS database.