Châteauneuf-sur-Sarthe (French pronunciation: [ʃɑtonœf syʁ saʁt] ) is a former commune in the Maine-et-Loire department of western France. On 1 January 2019, it was merged into the commune Les Hauts-d'Anjou. It is approximately 175 miles (280 km) from Paris. It had a population of 3,067 in 2022. The river Sarthe flows to the east of the town near where the Sarthe and river Mayenne join to form the river Maine.
Châteauneuf-sur-Sarthe is to the north of the Loire Valley, an area famous for its historic towns, wine-growing region and cultural landscape. The local areas is heavily farmed both for arable and pastoral uses.