The township was organized in 1858 and named for the adjacent city of Oronoco, which had formed in 1854.

The city was named by early settler Dr. Hector Galloway for the similarly spelled Orinoco, a large river in South America.

As of the census[2] of 2000, there were 2,239 people, 816 households, and 616 families residing in the township.

There were 872 housing units at an average density of 26.7 per square mile (10.3/km2).

17.8% of all households were made up of individuals, and 3.3% had someone living alone who was 65 years of age or older.