Orwell Township is bordered by Windham Township to the north, Warren Township to the north and east, Pike Township to the east, Herrick Township to the south and Rome Township to the west.
There were 402 households out of which 33.8% had children under the age of 18 living with them, 65.7% were married couples living together, 7.2% had a female householder with no husband present, and 22.4% were non-families. 17.9% of all households were made up of individuals and 8.7% had someone living alone who was 65 years of age or older. The average household size was 2.73 and the average family size was 3.07.
In the township the population was spread out with 27.1% under the age of 18, 6.8% from 18 to 24, 29.1% from 25 to 44, 22.9% from 45 to 64, and 14.1% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 98.7 males. For every 100 females age 18 and over, there were 101.0 males.
The median income for a household in the township was $36,635, and the median income for a family was $42,500. Males had a median income of $28,889 versus $21,985 for females. The per capita income for the township was $15,055. About 3.8% of families and 6.3% of the population were below the poverty line, including 4.2% of those under age 18 and 10.2% of those age 65 or over.