According to the United States Census Bureau, Ball Bluff township has a total area of 91.3 km² (35.3 mi²). 87.7 km² (33.9 mi²) of it is land and 3.7 km² (1.4 mi²) of it (4.03%) is water.

As of the census² of 2000, there were 300 people, 121 households, and 86 families residing in the township. The population density was 3.4/km² (8.9/mi²). There were 207 housing units at an average density of 2.4/km² (6.1/mi²). The racial makeup of the township was 98.67% White, 0.67% Native American, and 0.67% from two or more races.

There were 121 households out of which 28.9% had children under the age of 18 living with them, 62.0% were married couples living together, 3.3% had a female householder with no husband present, and 28.9% were non-families. 25.6% of all households were made up of individuals and 8.3% had someone living alone who was 65 years of age or older. The average household size was 2.48 and the average family size was 2.92.

In the township the population was spread out with 22.7% under the age of 18, 4.7% from 18 to 24, 25.3% from 25 to 44, 31.3% from 45 to 64, and 16.0% who were 65 years of age or older. The median age was 43 years. For every 100 females there were 102.7 males. For every 100 females age 18 and over, there were 101.7 males.

The median income for a household in the township was $33,750, and the median income for a family was $45,625. Males had a median income of $36,667 versus $21,500 for females. The per capita income for the township was $16,602. About 19.6% of families and 28.4% of the population were below the poverty line, including 47.9% of those under the age of eighteen and 10.5% of those sixty five or over.