Rensselaer County is a county in the U.S. state of New York. As of the 2020 census, the population was 161,130. 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. The county is part of the Capital District region of the state.

Troy is a city in the United States state of New York and is the county seat of Rensselaer County, New York. It's famous for being the home of Uncle Sam, known as the person who supplied beef for the United States Army during the War of 1812. It's also known for the home of Garnet Douglass Baltimore, who is known as the first African-American to become an engineer and graduated at Rensselaer Polytechnic Institute in 1881. It is located on the western edge of that county on the eastern bank of the Hudson River just northeast of the capital city of Albany. Troy has close ties to Albany, New York and nearby Schenectady, forming a region popularly called the Capital District.