Ralpho Township is a municipality located in Northumberland County, Pennsylvania. As of the 2010 census, the township population was 4,321.
According to the US Census Bureau, the township has a total area of 18.5 square miles, none of which is covered with water.
As of the census of 2010, there were 4,321 people, 1,797 households, and 1,295 families residing in the township. The population density was 233.6 people per square mile. There were 1,958 housing units at an average density of 105.9/sq mi. The racial makeup of the township was 98.4% White, 0.3% African-American, 0.1% Native American, 0.5% Asian, and 0.5% from two or more races. Hispanic or Latino of any race were 0.8% of the population.
There were 1,797 households out of which 25.7% had children under the age of 18 living with them, 61.8% were married couples living together, 7.1% had a female householder with no husband present, and 27.9% were non-families. 23.8% of households were made up of individuals and 12.4% had someone living alone who was 65 years of age or older. The average household size was 2.4 and the average family size was 2.83.
In the township the population was spread out with 20.0% under the age of 18, 2.7% from 18 to 20, 57.9% from 21 to 65, and 19.4% who were 65 years of age or older. The median age was 46.3 years. For every 100 females there were 93 males. For every 100 females age 18 and over, there were 90 males.
As of the 2015 American Community Survey, the median income for a household in the township was $52,344, and the median income for a family was $65,931. The per capita income for the township was $28,975. About 5.1% of families and 5.3% of the population were below the poverty line, including 5.6% of those under age 18 and 11.1% of those age 65 or over.