Marnay, on the Ognon road, is a fortified town on the river. The inhabited center at the foot of the castle dates from the 12th century. The primitive castle, built to monitor the passage of the Ognon and serve as a refuge for the inhabitants, is due to the Chalon family, younger branch of the Counts of Burgundy. After successive dominations in the County of Burgundy, the city became French when the province was united with the royal domain by Louis XIV in 1678.

The Saint Symphorien Church, registered in 1926, presents several architectural periods, from the 12th to the 17th century: the bell tower, restored in 1991, of barlong shape, its 14th century base garnished with arquebus loopholes, its summit rebuilt in the 15th century by the Counts of Neufchatel and topped with a high pyramid. The church, open during the day, preserves a magnificent pietà sculpted in the workshops of Brou where Laurent I of Gorrevod, lord of Marnay, directed the work on the tomb of Philibert the Beautiful. Let us also mention the painting of the Virgin of the Rosary, early 17th century by the Holbein school, the sculptures of Saint Nicholas, the Education of the Virgin, Saint Sebastian, the Stations of the Cross in enamelled terracotta. The apse is decorated with large Flamboyant Gothic style windows with stained glass from the 14th and 15th centuries.

The Hôtel de Santans, today the Hôtel de Ville, is a fine Renaissance example of urban civil architecture in the 16th century. Listed as MH in 1915, its large facade, made of blue-veined ocher limestone extracted from nearby quarries, has two levels with often paired mullioned windows and has retained the Santans coat of arms. The semicircular arch of the porch is topped by a console table, inspired by ancient temples.
Via the peasant streets, rue Bizot and rue Gambetta (formerly rue des Tisserands), the walk leads to the Chapuis farm, the former Hôtel des princes de Montbarrey, lords of Ruffey-le-Château, and the Bouchaton farm.
The remains of the old castle allow you to admire, after the entrance door where the lodge of the drawbridge arrows remains, the seigniorial residence in the interior courtyard, the remains of the archives pavilion and the polygonal tower, including the staircase preserves the angel playing the bagpipes.

Today the Petite Cité Comtoise de Caractère is a very lively village with its active associative fabric, its local shops, a leisure center and a **** campsite on the banks of the Ognon for lovers of family tourism, heart of a valley with still unspoiled nature.