John I, Count of Sancerre

John I (c. 1235–c. 1280/1284), son of Louis I and Blanche of Courtenay, became Count of Sancerre in 1268. In 1259 he married Marie de Vierzon, adding her lands to the county, and he built the fortress of La Vieille-Ferté in 1266.

In 1267 he assigned his wife's dower lands to his brother and gave her Sagonne in compensation. He sought to prevent the county's division.

He also confirmed the privileges of the bourgeois of Meillant and struck deniers and oboles at Sancerre. On his death he was succeeded by his son Stephen II.