Plattekill is a town in Ulster County, New York, United States. The population was 10,499 at the 2010 census. The name is derived from a stream, the Platte Kill.
According to the United States Census Bureau, the town has a total area of 35.7 square miles (92.5 km²), of which, 35.6 square miles (92.2 km²) of it is land and 0.1 square miles (0.2 km²) of it (0.22%) is water.
The south town line is the border of Orange County, dividing Plattekill from Newburgh. To the west, Plattekill borders Shawangunk and Gardiner, while in the north the town is bordered by Lloyd. The eastern boundary of the town closely parallels the Marlboro Mountain ridge, dividing Plattekill from the town of Marlborough.
The New York State Thruway (Interstate 87), US 44 (concurrent with NY 55) and NY 32 pass through the town.
As of the census of 2000, there were 9,892 people, 3,649 households, and 2,561 families residing in the town. The population density was 277.8 people per square mile (107.3/km²). There were 3,888 housing units at an average density of 109.2 per square mile (42.2/km²). The racial makeup of the town was 86.91% White, 4.62% Black or African American, 0.31% Native American, 0.63% Asian, 0.03% Pacific Islander, 5.06% from other races, and 2.44% from two or more races. Hispanic or Latino of any race were 16.00% of the population.
There were 3,649 households out of which 35.6% had children under the age of 18 living with them, 53.6% were married couples living together, 11.6% had a female householder with no husband present, and 29.8% were non-families. 23.7% of all households were made up of individuals and 8.0% had someone living alone who was 65 years of age or older. The average household size was 2.70 and the average family size was 3.19.
In the town, the population was spread out with 27.6% under the age of 18, 7.4% from 18 to 24, 30.8% from 25 to 44, 22.9% from 45 to 64, and 11.5% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 97.9 males. For every 100 females age 18 and over, there were 94.5 males.
The median income for a household in the town was $40,448, and the median income for a family was $47,684. Males had a median income of $36,675 versus $29,449 for females. The per capita income for the town was $18,651. About 6.3% of families and 9.6% of the population were below the poverty line, including 13.0% of those under age 18 and 7.3% of those age 65 or over.