Manlius is a town in Onondaga County, east of the city of Syracuse, New York, United States. The population was 32,370 at the 2010 census, making it the third largest suburb in metropolitan Syracuse. In 2005, the town was ranked #98 on CNN Money's list of Best Places to Live.
The town was a township of the former Central New York Military Tract. Manlius is the name of several important Romans, but exactly which one was being honored is no longer known. The current town was first settled around 1790.
The Town of Manlius was created in 1813, along with Onondaga County, as a much larger entity, which was decreased by the formation, in part or in whole, of new towns (DeWitt, Onondaga, Salina) and part of Syracuse.
The economy related to trade generated by the Erie Canal contributed to the early development of the town.