[4] According to the United States Census Bureau, the township has a total area of 11.9 square miles (31 km2), all land.

It is named after former United States Secretary of State and Republican candidate for the 1884 presidential election, James G. Blaine, a native of West Brownsville in Washington County.

At the 2000 census there were 597 people, 217 households, and 172 families living in the township.

The population density was 50.4 inhabitants per square mile (19.5/km2).

[5] Of the 217 households, 39.6% had children under the age of 18 living with them, 71.9% were married couples living together, 6.0% had a female householder with no husband present, and 20.3% were non-families.