Menallen Township is a township that is located in Adams County, Pennsylvania, United States. The population was 3,515 at the time of the 2010 census.^[3]

This American township is named after an older variant spelling of Moyallen, County Down, now in Northern Ireland.^[4]

According to the United States Census Bureau, the township has a total area of 42.8 square miles (110.9 km²), of which 42.7 square miles (110.6 km²) is land and 0.12 square miles (0.3 km²), or 0.29%, is water.^[3]

As of the census^[6] of 2000, there were 2,974 people, 1,077 households, and 818 families residing in the township.

The population density was 69.5 inhabitants per square mile (26.8/km²). There were 1,229 housing units at an average density of 28.7 per square mile (11.1/km²).

The racial makeup of the township was 93.38% White, 0.91% African American, 0.20% Native American, 0.03% Asian, 0.03% Pacific Islander, 4.10% from other races, and 1.34% from two or more races. Hispanic or Latino of any race were 9.18% of the population.

There were 1,077 households, out of which 34.5% had children under the age of eighteen living with them; 64.3% were married couples living together, 7.2% had a female householder with no husband present, and 24.0% were non-families. 18.9% of all households were made up of individuals, and 7.2% had someone living alone who was sixty-five years of age or older.

The average household size was 2.73 and the average family size was 3.12.

Within the township, the population was spread out, with 26.2% of residents who were under the age of eighteen, 8.1% who were aged eighteen to twenty-four, 30.2% who were aged twenty-five to forty-four, 23.9% who were aged forty-five to sixty-four, and 11.5% who were sixty-five years of age or older. The median age was thirty-seven years.

For every one hundred females there were 104.8 males. For every one hundred females who were aged eighteen or older, there were 103.5 males.

The median income for a household in the township was $41,404, and the median income for a family was $43,615. Males had a median income of $30,786 compared with that of $23,523 for females.

The per capita income for the township was $17,415.

Approximately 7.3% of families and 8.4% of the population were living below the poverty line, including 8.7% of those who were under the age of eighteen and 15.8% of those who were aged sixty-five or older.