Essex County is a county located in the U.S. state of New York. As of 2000, the population was 38,851. Its name is from the English county of Essex. Its county seat is Elizabethtown. When counties were established in New York State in 1683, the present Essex County was part of Albany County. This was an enormous county, including the northern part of New York State as well as all of the present State of Vermont and, in theory, extending westward to the Pacific Ocean. This county was reduced in size on July 3, 1766 by the creation of Cumberland County, and further on March 16, 1770 by the creation of Gloucester County, both containing territory now in Vermont. On March 12, 1772, what was left of Albany County was split into three parts, one remaining under the name Albany County. One of the other pieces, Charlotte County, contained the eastern portion.

As of the census˛ of 2000, there were 38,851 people, 15,028 households, and 9,828 families residing in the county. The population density was 8/km˛ (22/mi˛). There were 23,115 housing units at an average density of 5/km˛ (13/mi˛). The racial makeup of the county was 94.84% White, 2.81% Black or African American, 0.31% Native American, 0.41% Asian, 0.07% Pacific Islander, 0.69% from other races, and 0.86% from two or more races. 2.19% of the population were Hispanic or Latino of any race.