The elevation near the
mouth of Little Darby Creek is above
sea level. The elevation of the creek's
source is between above sea level. Two soil associations exist in the Little Darby Creek watershed. The Neshaminy-Lehigh-Glenlg soil association is prevalent in much of the watershed. It consists of silty, well drained, gravelly, and deep soil that rests on
gabbro and
granodiorite bedrock. The Chester-Glenlg-Manor soil association is prevalent through the middle of the watershed. It consists of silty, channery, and shallow to deep soil that rests on brown
schist and
gneiss bedrock. Most of the watershed is considered to have slightly erodible soil. ==Watershed==