According to the United States Census Bureau, the township has a total area of, of which, of it is land and of it is water. It is drained by the Delaware River which forms its eastern boundary with New Jersey. Its villages include Durham, Durham Furnace, Kintnersville Lehnenburg, Morgantown, Monroe, and Rattlesnake. Route 611 is north-to-south while Route 212 is east-to-west and meets it in Durham Furnace. Natural features include Brandywine Creek, Chestnut Hill, Cooks Creek, Durham Cave, Durham Creek, Durham Hill, Molasses Creek, and Rodges Run.
As of the 2010 census, the township was 96.6% White, 0.3% Black or African American, 0.1% Native American, 1.0% Asian, and 0.7% were two or more races. 1.3% of the population were of Hispanic or Latino ancestry. As of the census of 2000, there were 1,313 people, 485 households, and 382 families residing in the township. The population density was 142.6 people per square mile. There were 525 housing units at an average density of 57.0/sq mi. The racial makeup of the township was 98.17% White, 0.08% African American, 0.76% Asian, 0.23% from other races, and 0.76% from two or more races. Hispanic or Latino of any race were 1.07% of the population. There were 485 households, out of which 34.8% had children under the age of 18 living with them, 70.5% were married couplesliving together, 4.5% had a female householder with no husband present, and 21.2% were non-families. 17.3% of all households were made up of individuals, and 6.4% had someone living alone who was 65 years of age or older. The average household size was 2.71 and the average family size was 3.07. In the township the population was spread out, with 23.9% under the age of 18, 6.8% from 18 to 24, 28.1% from 25 to 44, 29.3% from 45 to 64, and 11.9% who were 65 years of age or older. The median age was 41 years. For every 100 females, there were 114.5 males. For every 100 females age 18 and over, there were 110.8 males. The median income for a household in the township was $70,875, and the median income for a family was $73,750. Males had a median income of $51,719 versus $34,688 for females. The per capita income for the township was $29,913. 3.9% of the population and 2.7% of families were below the poverty line. Out of the total population, 3.0% of those under the age of 18 and 3.0% of those 65 and older were living below the poverty line.
Climate
According to the Köppen climate classification system, Durham Twp has a Hot-summer, Humid continental climate. Dfa climates are characterized by at least one month having an average mean temperature ≤, at least four months with an average mean temperature ≥, at least one month with an average mean temperature ≥ and no significant precipitation difference between seasons. Although most summer days are slightly humid in Durham Twp, episodes of heat and high humidity can occur with heat index values >. Since 1981, the highest air temperature was on 07/22/2011, and the highest daily average mean dew point was on 08/01/2006. The average wettest month is July which corresponds with the annual peak in thunderstorm activity. Since 1981, the wettest calendar day was on 08/27/2011. During the winter months, the average annual extreme minimum air temperature is. Since 1981, the coldest air temperature was on 01/21/1994. Episodes of extreme cold and wind can occur with wind chill values <. The average annual snowfall is between and. Ice storms and large snowstorms depositing ≥ of snow occur once every few years, particularly during nor’easters from December through February.
