The northern part of Eure-et-Loir is watered by the Eure, with its tributaries the Vegre, Blaise and Avre, a small western portion by the Huisne, and the south by the Loir with its tributaries the Conic and the Ozanne.
Market gardens, known as hortillonnages, intersected by small canals derived from the Somme and Avre, cover a considerable area to the north-east of Amiens; and the city has trade in vegetables, as well as in grain, sugar, wool, oil-seeds and the duck-pasties and macaroons for which it is renowned.
All the rivers of the department flow into the Seine, - on the right bank the Andelle and the Epte, and on the left the Eure with its tributaries the Avre and the Iton, and the Risle with its tributary the Charentonne.