Middlefield is a town in Otsego County, New York, United States. The population was 2,114 at the 2010 census.
According to the United States Census Bureau, the town has a total area of 65.9 square miles (171 km), of which, 64.4 square miles (167 km) of it is land and 1.5 square miles (3.9 km) of it (2.32%) is water.
New York State Route 166 follows the course of Cherry Valley Creek through the south part of the town. Cherry Valley Creek and Red Creek, which drain the town, are tributaries of the Susquehanna River.
The western part of Middlefield borders Otsego Lake.
As of the census of 2000, there were 2,249 people, 792 households, and 564 families residing in the town. The population density was 34.9 people per square mile (13.5/km²). There were 1,058 housing units at an average density of 16.4 per square mile (6.3/km²). The racial makeup of the town was 96.31% White, 1.11% African American, 0.22% Native American, 0.89% Asian, 0.31% from other races, and 1.16% from two or more races. Hispanic or Latino of any race were 1.24% of the population.
There were 792 households out of which 32.6% had children under the age of 18 living with them, 58.8% were married couples living together, 7.3% had a female householder with no husband present, and 28.7% were non-families. 24.1% of all households were made up of individuals and 10.9% had someone living alone who was 65 years of age or older. The average household size was 2.52 and the average family size was 2.98.
In the town, the population was spread out with 22.5% under the age of 18, 6.0% from 18 to 24, 23.9% from 25 to 44, 25.2% from 45 to 64, and 22.4% who were 65 years of age or older. The median age was 43 years. For every 100 females, there were 96.4 males. For every 100 females age 18 and over, there were 89.8 males.
The median income for a household in the town was $39,625, and the median income for a family was $43,750. Males had a median income of $34,583 versus $25,795 for females. The per capita income for the town was $21,076. About 5.0% of families and 7.0% of the population were below the poverty line, including 8.4% of those under age 18 and 6.8% of those age 65 or over.