Rensselaer County /rɛnsəˈlɪər/ is a county in the U.S. state of New York. As of the 2010 census, the population was 159,429. Its county seat is Troy. The county is named in honor of the family of Kiliaen van Rensselaer, the original Dutch owner of the land in the area.
According to the U.S. Census Bureau, the county has a total area of 665 square miles (1,720 km), of which 652 square miles (1,690 km) is land and 13 square miles (34 km) (1.9%) is water.
Rensselaer County is in the eastern part of New York State. The eastern boundary of Rensselaer County runs along the New York–Vermont and New York–Massachusetts borders.
The terrain runs from level and flat near the Hudson and then rises into the Rensselaer Plateau around Poestenkill and Sand Lake, then to the Taconic Mountains along the Massachusetts state line.
The highest point is Berlin Mountain, 2,818 feet (859 m) above sea level, in the town of Berlin. The lowest point is 62 feet (19 m) above sea level at the Hudson River’s southernmost extent in the county.
The Hoosic River, a tributary of the Hudson River, is in the north part of the county.
Depending on precise location within the county, road travel distance to New York City ranges between 132 miles (212 km) and 178 miles (286 km).
As of the census of 2010, there were 161,129 people, 62,694 households, and 39,989 families residing in the county. The population density was 233 people per square mile (90/km²). There were 69,120 housing units at an average density of 109 per square mile (39/km²). The racial makeup of the county was 88.73% White, 7.14% Black or African American, 0.23% Native American, 1.71% Asian, 0.02% Pacific Islander, 0.89% from other races, and 1.34% from two or more races. 5.01% of the population were Hispanic or Latino of any race. 22.3% were of Irish, 14.7% Italian, 12.8% German, 7.5% English, 6.2% French, 5.3% American and 2.3% Puerto Rican ancestry according to Census 2010. 95.4% spoke English and 2.7% Spanish as their first language.
There were 61,094 households out of which 33.30% had children under the age of 18 living with them, 46.80% were married couples living together, 12.00% had a female householder with no husband present, and 34.80% were non-families. 27.90% of all households were made up of individuals and 10.30% had someone living alone who was 65 years of age or older. The average household size was 2.46 and the average family size was 3.02.
In the county, the population was spread out with 24.20% under the age of 18, 10.10% from 18 to 24, 29.10% from 25 to 44, 23.00% from 45 to 64, and 13.60% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 95.90 males. For every 100 females age 18 and over, there were 93.70 males.
The median income for a household in the county was $42,905, and the median income for a family was $52,864. Males had a median income of $36,666 versus $28,153 for females. The per capita income for the county was $21,095. About 6.70% of families and 9.50% of the population were below the poverty line, including 11.90% of those under age 18 and 6.60% of those age 65 or over.