Active Adult 55 & Over Condos for Sale in Nassau County There are 28 active adult condos for sale in Nassau County. Prices start at $125,000 for a one bedroom condo in The Tiffany development located in Westbury, NY to $999,000 for a three bedroom, seven room condo in the Harbor View development Port Washington, NY. Active Adult communities in Nassau County doesn't always mean 55 and over. Some active adult communities in Nassau County will have the minimum age requirement at 60 or over. Although there are active adult condos in Nassau County for sale, if you do not want anyone living (2 comments)