Cassian is a town in Oneida County, Wisconsin, United States.

The unincorporated communities of Goodnow and Harshaw are located in the town.

There were 1,011 housing units at an average density of 15.6 per square mile (6.0/km2).

15.2% of all households were made up of individuals, and 6.2% had someone living alone who was 65 years of age or older.

The Rhinelander-Oneida County Airport (KRHI) serves Cassian, the county and surrounding communities with both scheduled commercial jet service and general aviation services.