Orne is a département in the northwest of France, named after the river Orne. It had a population of 279,942 in 2019. Orne is one of the origi…Orne is a département in the northwest of France, named after the river Orne. It had a population of 279,942 in 2019. Orne is one of the original 83 départements created during the French Revolution, on 4 March 1790. It was created from parts of the former provinces of Normandy and Perche. It is the birthplace of Charlotte Corday, Girondist and the assassin of Jean-Paul Marat.