Population (2004) 1,339,641

A giant population wave changed Nassau County, almost overnight from a rural farming community to the nation's largest suburb. So frenetic was the growth during the 1950's that the number of people moving into the county in a single year often surpassed the entire population of 55,448 in 1900. The population doubled in ten years from 1950 to 1960, increasing from 672,000 to 1,300,700, reaching a peak of 1,428,838 in 1970. Major redevelopment of the east/west parkway systems created just before World War II were supplemented by the creation of additional north/south parkways and the Long Island Expressway.

In the subsequent decades of the 1980's and '90's, population growth ceased but the county's economic base and business/educational/recreational infrastructure changed dramatically as every aspect matured within the changes affecting all of America. Manufacturing, particularly the aviation industry, declined while retail and service employment boomed. A dramatic increase in office construction with some buildings exceeding over 1,000,000 square feet, changed the Nassau horizon and established it as a major place of white collar employment. Nassau County family income is in the top ten percent of the nation with the number one retail sales per household.

While these dramatic economic changes occurred, other institutional development flourished. Local government responded to contemporary problems and the county Board of Supervisors was changed to a more widely representative County Legislature in 1996. The county's educational system of independent local school districts is acclaimed as among the best in the nation and is enhanced by strong local colleges and universities. An increasing ethnic diversity of its population in the 1990's has enriched the county's cultural and religious life.