Ombrone was a former département during the First French Empire in modern-day Italy. It was named after the river Ombrone and was formed in 1808 when Tuscany was annexed by France. Its capital was Siena. The département was subdivided into the following arrondissements and cantons (situation in 1812):
- Siena, cantons: Bucine, Colle, Chiusdino, Poggibonsi, Radda, Radicondoli, Rapolano, Siena (2 cantons) and Sovicille.
- Grosseto, cantons: Arcidosso, Campagnatico, Santa Fiora, Isola del Giglio, Grosseto, Massa, Manciano, Orbetello, Pitigliano, Roccastrada and Scansano.
- Montepulciano, cantons: Abbadia San Salvatore, Asinalunga, Chiusi, Montalcino, Montepulciano, Pienza and Sarteano.
Its population in 1812 was 189,307, and its area was 774,897 hectares.
The département was disbanded after the defeat of Napoleon I in 1814. Today its territory is divided between the Italian provinces of Siena, Arezzo and Grosseto.