Nassau County is located on Long Island in the US state of New York. It is the most populous county in the state outside of New York City and ranks fourth in terms of population density. The county seat is Mineola, which is also the county's largest city.

Nassau County is a provisioning county and is governed by a Board of Supervisors. The County has a County Executive branch. The County Executive is elected by popular vote. The County Executive is responsible for the budget and fiscal operations, personnel, public works and infrastructure, and social services and health care. The County Legislature is composed of 19 members representing the 19 towns, two cities, and two Native American nations in the County. The County Legislature is the legislative body of the county and is responsible for passing laws, setting budgets, and determining the County's legislative priorities.

Nassau County is home to several major universities, including Hofstra University, Adelphi University, and Nassau Community College. It is also home to several major parks, including Jones Beach State Park, Bethpage State Park, and Eisenhower Park.

Nassau County is served by the Nassau County Police Department, the Nassau County Sheriff's Office, and the Nassau County Fire Marshal's Office. The county is also served by the Long Island Rail Road and the Nassau Inter-County Express bus system.

For the most up-to-date and in-depth information, please check the public records links below.