Tarn (French pronunciation: [taʁn] or [ta:ʁ]; Occitan pronunciation: [taɾ]) is a department in the Occitania region in Southern France. Named after the river Tarn, it had a population of 389,844 as of 2019. Its prefecture and largest city is Albi; it has a single subprefecture, Castres. In French, the inhabitants of Tarn are known as Tarnais (masculine) and Tarnaises (feminine). Its INSEE and postcode number is 81.

Tarn is one of the original 83 departments created during the French Revolution on 4 March 1790, through application of the Law of 22 December 1789. It was created from part of the former province of Languedoc, and comprised the dioceses of Albi and Castres (which found themselves merged in 1817).

The new department had five districts: Albi, Castres, Lavaur, Gaillac, Lacaune. The capitals (now prefectures) were, alternatively, Albi and Castres but, from 1790 to 1797, the capital was only Albi; in 1797, the capital was moved to Castres. In 1800, Albi became again the capital of the department and the arrondissements were created; the department had four arrondissements: Albi, Castres, Gaillac and Lavaur. In 1926, the arrondissements of Gaillac and Lavaur were eliminated.

By the law of 28 Pluviôse Year 5, the departments of Hérault and of Tarn exchanged the canton of Anglès (which had been part of the diocese of Saint-Pons, but which has remained in Tarn) for that of Saint-Gervais-sur-Mare (which had been part of the diocese of Castres, but which today remains in Hérault).

Tarn is part of the Occitanie region and has an area of 5,757.9 km (2,223 sq mi). The department is surrounded by 5 departments, all belonging to the region Occitanie: Hérault to the southeast, Aude to the south, Aveyron to the north and east, Haute-Garonne to the southwest and west, as well as Tarn-et-Garonne to the northwest. It is one of two French departments surrounded entirely by other departments of the same region.

The slope of the department is from east to west, and its general character is mountainous or hilly. Tarn's three principal ranges lying to the south-east are: the Mountains of Lacaune, the Sidobre and the Montagne Noire, belonging to the Cévennes.

The stony and wind-blown slopes of the Mountains of Lacaune (Monts de Lacaune) are used for pasture. The highest point of the range and of the department is the Puech Montgrand, 1,267 m (4,157 ft) high; several other summits are not much short of this. The granite-strewn plateaux of the Sidobre, from 490 to 610 m (1,600 to 2,000 ft) high, separate the valley of the river Agout from that of its western tributary, the Thoré River. The Montagne Noire, on the southwestern border of the department, derives its name from the forests on its northern slope. Its highest point is the Pic de Nore at 1,211 m (3,973 ft) high.

The limestone and sandstone foot-hills are clothed with vines and fruit trees, and are broken by deep alluvial valleys of particular fertility. With the exception of a small portion of the Montagne Noire, which drains into the river Aude, the whole department belongs to the basin of the Garonne.

Tarn has a population, in 2019, of 389,844, for a population density of 67.7 inhabitants/km.

Population development since 1801:

Historical population

Year Pop. ±% p.a. 1801 270,908 —     1806 296,228 +1.80% 1821 313,713 +0.38% 1831 335,844 +0.68% 1841 351,795 +0.47% 1851 363,073 +0.32% 1861 353,633 −0.26% 1872 352,718 −0.02% 1881 359,223 +0.20% 1891 346,739 −0.35% 1901 332,093 −0.43% 1911 324,090 −0.24% 1921 295,588 −0.92%	Year Pop. ±% p.a. 1931 302,994 +0.25% 1936 297,871 −0.34% 1946 298,117 +0.01% 1954 308,197 +0.42% 1962 319,560 +0.45% 1968 332,011 +0.64% 1975 338,024 +0.26% 1982 339,345 +0.06% 1990 342,723 +0.12% 1999 343,402 +0.02% 2006 365,337 +0.89% 2011 377,675 +0.67% 2016 386,448 +0.46%
Graphs are unavailable due to technical issues. There is more info on Phabricator and on MediaWiki.org.
Sources:

The most populous commune is Albi, the prefecture. As of 2019, there are 10 communes with more than 6,000 inhabitants:

Commune	Population (2019)
Albi	48,902
Castres	42,079
Gaillac	15,265
Graulhet	12,844
Lavaur	10,879
Mazamet	9,996
Carmaux	9,782
Saint-Sulpice-la-Pointe	9,336
Saint-Juéry	6,694
Labruguière	6,506

There are 2 arrondissements, 23 cantons and 314 communes in Tarn.

Arrondissement	INSEE code	Capital	Population (2019)	Area (km)	Density (inhabitants/km)	Communes
Albi	811	Albi	193,307	2,732	70.8	163
Castres	812	Castres	196,537	3,026	64.9	151

The Departmental Council of Tarn has 46 seats. In the 2015 departmental elections, the Socialist Party (PS) won 26 seats and The Republicans (LR) and Union of Democrats and Independents (UDI) alliance won 18 seats; two miscellaneous right candidates complete the assembly composition. Christophe Ramond (PS) has been President of the Departmental Council since 2017.

In the 2017 legislative election, Tarn elected the following members of the National Assembly:

Constituency		Member	Party
	Tarn's 1st constituency	Philippe Folliot	Centrist Alliance
	Tarn's 2nd constituency	Marie-Christine Verdier-Jouclas	La République En Marche!
	Tarn's 3rd constituency	Jean Terlier	La République En Marche!

• 
  Palais de la Berbie Albi
• 
  Albi Cathedral
• 
  Castres The theater and the Goya Museum (Episcopal Palace) seen from the bishop's garden
• 
  Street in Castelnau-de-Montmiral
• 
  View of Cordes-sur-Ciel
• 
  Street in Penne

• Cantons of the Tarn department
• Communes of the Tarn department
• Arrondissements of the Tarn department
• Tourism in Tarn

• Departmental Council website (in French)
• Prefecture website (in French)
• Discover Tarn – Comité Départemental du Tourisme du Tarn
• Photos of the Tarn (in French)