REPORT OF INVESTIGATIONS NO. 40 and two sides of Santa Rosa County. The Perdido River is the boundary line between Florida and Alabama on the west and the Escambia River separates the two counties. Santa Rosa is the larger, but less populous county, with 1,151 square miles and a 1960 population density of 25.6 persons per square mile. Escambia County covers 759 square miles and had a 1960 population density of 229 persons per square mile. Figure 1. Map of Florida showing location of Escambia and Santa Rosa counties. The two major cities in the area are Pensacola and Milton. Pensacola, located in southern Escambia County on Pensacola Bay, had a population of 56,752 in 1960. Greater Pensacola includes several small suburban communities and thus has a much greater population than Pensacola proper. Milton is the largest town in Santa Rosa County, with a popula- tion of 4,108 in 1960. Much of the land in the southern part of the area is less than 30 feet above sea level. Bays, low marshy areas, peninsulas, and islands with long shorelines characterize this section. Estuarine bays extend inland some 20 miles and cover over 200 square miles. Santa Rosa Island is about half a mile wide and 55 miles long and extends from the mouth