“The many old provinces and parlements of France were swept away by the French Revolution. On 4 March 1791, France was divided into 83 new department units, named after unitary geographic units such as valley or mountain range. Each was to be governed by and official, the all-powerful Intendant, appointed by the central government. These officials were instructed to establish a departmental capital so that no area should be more than a day’s ride from the head office. At the height of the conquests of Napoleon, the efficient bureaucratic Empire of Departements expanded to 130, but it later reverted to 86. In 1860, the seizure of Nice and Savoy from Italy took the number up to 89, whilst victory in the First World War allowed for the Alsatian fortress of Belfort to become number 90. Further reorganization and the addition of five overseas departements brought the number to its current tally of 101.”
Excerpted from: Rogerson, Barnaby. Rogerson’s Book of Numbers: The Culture of Numbers–from 1,001 Nights to the Seven Wonders of the World. New York: Picador, 2013.