Marilla is a town in Erie County, New York, United States. The population was 5,327 at the 2010 census. The name of the town is derived from Marilla Rogers, an early school teacher.
According to the United States Census Bureau, the town has a total area of 27.54 square miles (71.34 km), of which 27.51 square miles (71.24 km) is land and 0.04 square miles (0.10 km), or 0.14%, is water.
Buffalo Creek flows through the southwest part of the town, and Cayuga Creek flows through the northeast part of town.
As of the census of 2000, there were 5,709 people, 2,021 households, and 1,616 families residing in the town. The population density was 207.2 people per square mile (80.0/km²). There were 2,088 housing units at an average density of 75.8 per square mile (29.3/km²). The racial makeup of the town was 99.09% White, 0.12% African American, 0.07% Native American, 0.16% Asian, 0.02% Pacific Islander, 0.14% from other races, and 0.40% from two or more races. Hispanic or Latino of any race were 0.46% of the population.
There were 2,021 households out of which 36.8% had children under the age of 18 living with them, 69.1% were married couples living together, 8.2% had a female householder with no husband present, and 20.0% were non-families. 17.0% of all households were made up of individuals and 6.4% had someone living alone who was 65 years of age or older. The average household size was 2.82 and the average family size was 3.21.
In the town, the population was spread out with 27.2% under the age of 18, 7.1% from 18 to 24, 27.4% from 25 to 44, 27.2% from 45 to 64, and 11.1% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 98.7 males. For every 100 females age 18 and over, there were 98.0 males.
The median income for a household in the town was $51,868, and the median income for a family was $56,572. Males had a median income of $41,477 versus $23,700 for females. The per capita income for the town was $23,820. About 2.6% of families and 3.7% of the population were below the poverty line, including 4.6% of those under age 18 and 4.9% of those age 65 or over.