Location of Cassel, Wisconsin
Latitude and Longitude:
|• Total||33.0 sq mi (85.6 km2)|
|• Land||33.0 sq mi (85.5 km2)|
|• Water||0.0 sq mi (0.0 km2)|
|Elevation||1,270 ft (387 m)|
|• Density||28/sq mi (11/km2)|
|Time zone||UTC-6 ( Central (CST))|
|• Summer ( DST)||UTC-5 (CDT)|
|Area code(s)||715 & 534|
|FIPS code||55-12975 |
|GNIS feature ID||1582925 |
According to the United States Census Bureau, the town has a total area of 33.0 square miles (85.5 km²), of which 33.0 square miles (85.5 km²) is land and 0.03% is water.
As of the census  of 2000, there were 847 people, 271 households, and 223 families living in the town. The population density was 25.6 people per square mile (9.9/km²). There were 286 housing units at an average density of 8.7 per square mile (3.3/km²). The racial makeup of the town was 97.40% White, 0.12% African American, 1.77% Asian, and 0.71% from two or more races. Hispanic or Latino of any race were 0.47% of the population.
There were 271 households out of which 43.2% had children under the age of 18 living with them, 75.6% were married couples living together, 3.3% had a female householder with no husband present, and 17.7% were non-families. 15.1% of all households were made up of individuals and 6.3% had someone living alone who was 65 years of age or older. The average household size was 3.10 and the average family size was 3.49.
In the town, the population was spread out with 31.2% under the age of 18, 7.8% from 18 to 24, 28.6% from 25 to 44, 20.4% from 45 to 64, and 12.0% who were 65 years of age or older. The median age was 35 years. For every 100 females, there were 110.2 males. For every 100 females age 18 and over, there were 107.5 males.
The median income for a household in the town was $52,614, and the median income for a family was $55,938. Males had a median income of $35,268 versus $22,434 for females. The per capita income for the town was $22,818. About 7.8% of families and 9.4% of the population were below the poverty line, including 10.6% of those under age 18 and 13.8% of those age 65 or over.
- Leo Gesicki, businessman and politician, was born in the town. 
- Francis X. Schilling, farmer and politician, was born in the town. 
- "US Board on Geographic Names". United States Geological Survey. 2007-10-25. Retrieved 2008-01-31.
- "American FactFinder". United States Census Bureau. Archived from the original on 2013-09-11. Retrieved 2008-01-31.
- "Profile of General Population and Housing Characteristics: 2010 Demographic Profile Data (DP-1): Cassel town, Marathon County, Wisconsin". U.S. Census Bureau, American Factfinder. Archived from the original on September 11, 2013. Retrieved September 10, 2012.
- 'Wisconsin Blue Book 1931,' Biographical Sketch of Leo J. Gesicki, pg. 227
- 'Wisconsin Blue Book 1913,' Biographical Sketch of F.X. Schilling, pg. 668-669