Tarn is part of the
Occitanie region and has an area of . The department is surrounded by five 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, high; several other summits are not much short of this. The granite-strewn plateaux of the
Sidobre, from 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 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. ==Demographics==