Lyndhurst is a city in Cuyahoga County, Ohio, United States, and an eastern suburb of Cleveland. The population was 14,050 at the 2020 …Lyndhurst is a city in Cuyahoga County, Ohio, United States, and an eastern suburb of Cleveland. The population was 14,050 at the 2020 census. A small part of Lyndhurst was originally part of Mayfield Township.