Marcellus is a town in Onondaga County, New York, United States. The population was 6,319 at the 2000 census. The town was probably named after Marcus Claudius Marcellus, a Roman general, by a clerk interested in the Classics. Marcellus apartments for rent comparison page shows most up to date rent information on Marcellus apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.