Guernsey is a town in Platte County, Wyoming, United States. The population was 1,147 at the 2010 census.
The town was named for C. A. Guernsey, a cattle rancher.
Guernsey is located at 42°16′2″N 104°44′35″W (42.267251, −104.743187).
According to the United States Census Bureau, the town has a total area of 1.04 square miles (2.69 km2), of which 1.02 square miles (2.64 km2) is land and 0.02 square miles (0.05 km2) is water.
As of the census of 2010, there were 1,147 people, 504 households, and 315 families living in the town. The population density was 1,124.5 inhabitants per square mile (434.2/km2). There were 581 housing units at an average density of 569.6 per square mile (219.9/km2). The racial makeup of the town was 93.6% White, 0.2% African American, 0.5% Native American, 0.4% Asian, 3.5% from other races, and 1.7% from two or more races. Hispanic or Latino of any race were 13.1% of the population.
There were 504 households, of which 26.6% had children under the age of 18 living with them, 48.0% were married couples living together, 9.5% had a female householder with no husband present, 5.0% had a male householder with no wife present, and 37.5% were non-families. 30.4% of all households were made up of individuals, and 11.1% had someone living alone who was 65 years of age or older. The average household size was 2.28 and the average family size was 2.83.