The township was named for Pleasant Valley, New York by its first settler, Sylvester Hills.

Hoover, a first cousin of then-President Herbert Hoover traveled with two other farmers to Des Moines, Iowa (about 200 miles away) to secure a compromise on the foreclosure of his farm.

According to the United States Census Bureau, the township has a total area of 30.1 square miles (78.0 km2), all land.

19.0% of all households were made up of individuals, and 8.0% had someone living alone who was 65 years of age or older.

About 2.6% of families and 3.0% of the population were below the poverty line, including 4.3% of those under the age of eighteen and none of those 65 or over.