The majority of the land in the city is of karst topography, characterized by rolling hills and an abundant amount of lakes. The St. Johns River passes through Lake Monroe, directly south of the city. The United States Geological Survey lists the city's elevation at above sea level at a point near Deltona's geographic center. Elevations range from to above sea level. , according to the United States Census Bureau, the city has a total area of , of which is land and of which is water.