The Territoire de Belfort (French pronunciation: [tɛʁitwaʁ də bɛlfɔʁ] ; lit. "Territory of Belfort") is a department in the northeastern French region of Bourgogne-Franche-Comté. In 2020 it had a population of 140,120. The department, which encompasses a relatively small surface area of 609.4 km (235.3 sq mi), is located just southwest of the European Collectivity of Alsace. It also shares a border with the Swiss canton of Jura to the southeast. Its prefecture is Belfort.

The administrative district Territoire de Belfort was created under the terms of the 1871 Treaty of Frankfurt. The German Empire annexed almost all of Alsace, but the French were able to negotiate retention of the Territoire de Belfort which thereby was separated from the rest of Alsace (where it had been part of the department of Haut-Rhin). There were three principal reasons for this exceptional treatment:

• The population in and around Belfort was French-speaking.
• Belfort had demonstrated heroic resistance, under Colonel Pierre Denfert-Rochereau, to the German invasion. Belfort's left-wing Catholic Deputy Émile Keller now conducted a similarly forceful political campaign in the National Assembly. He argued that ceding heroic Belfort to Germany after the war would be unthinkable.
• Since Belfort is situated in a relatively flat passage between the Vosges and Jura mountain ranges (known as the Belfort Gap), the Germans agreed to leave the city in France, because the Prussian military officers indicated that this strategy would give Germany a more defensible border.

After retaining its unique status as a territoire for just over half a century, Belfort was officially recognized as France's 90th department in 1922. France had recovered Alsace three years earlier, but the decision was taken not to reintegrate Belfort into its former department. There was talk of giving it a new departmental name, with suggestions that included "Savoureuse" (after the main river of the new department) or "Mont-Terrible" (the name of a former Napoleonic department embracing parts of Switzerland), but there was no consensus for a name change and the department continues to be known as the Territoire de Belfort.

When the regions of France were created, Belfort was not included in the region of Alsace, but the adjacent region of Franche-Comté, since January 2016 Bourgogne-Franche-Comté.

Geographers might contend that Belfort lies on the ridge that divides two regions of France, but before 1870 it was politically part of Alsace. However, in terms of the political regions established in 1982, the Territoire de Belfort has found itself in the Franche-Comté rather than Alsace.

The department has an area of only 609 km (235 sq. miles), being the fifth smallest of Metropolitan France (after Paris and its suburbs Hauts-de-Seine, Seine-Saint-Denis, and Val-de-Marne). It is slightly smaller than Saint Lucia or Jakarta, Indonesia.

The most populous commune is Belfort, the prefecture. As of 2019, there are 4 communes with more than 5,000 inhabitants:

Commune	Population (2019)
Belfort	46,443
Delle	5,667
Valdoie	5,269
Beaucourt	5,010

The median net income per household for the department in 2017 was €21,310. The averaged figure for the Territoire de Belfort masked relatively large disparities such as, in particular, that between Belfort itself at €17,920 and Bermont at €26,600.

In 2019 the department recorded a population of 141,318. Of these, slightly more than 46,000 live in the commune of Belfort itself, which accounts more than 32% of the departmental population.

Historical population

Year Pop. ±% p.a. 1872 56,781 —     1881 74,244 +3.02% 1891 83,670 +1.20% 1901 92,304 +0.99% 1911 101,386 +0.94% 1921 94,338 −0.72% 1931 99,403 +0.52% 1936 99,497 +0.02% 1946 86,648 −1.37% 1954 99,427 +1.73%	Year Pop. ±% p.a. 1962 109,371 +1.20% 1968 118,450 +1.34% 1975 128,125 +1.13% 1982 131,999 +0.43% 1990 134,097 +0.20% 1999 137,408 +0.27% 2006 141,201 +0.39% 2011 143,348 +0.30% 2016 144,089 +0.10%
Graphs are unavailable due to technical issues. There is more info on Phabricator and on MediaWiki.org.
Sources:

Four principal phases can be identified in the population trends during the two centuries between 1801 and 2000.

• the period from 1800 to 1872 was marked by steady economic development and a relatively high birth rate. However, the cholera epidemic which in 1851 arose from increasing urbanisation, along with a more general economic slow-down, reduced the rate of increase in the third quarter of the century. Between 1803 and 1872 the recorded population increased from 37,558 to 56,781.
• after the loss to Germany of most of Alsace in 1871, the Belfort population was boosted by the arrival of large numbers of refugees from "Germanisation": the years between 1871 and 1914 saw the development of large factories, with the mechanical and textile sectors being prominent growth areas. The population increase and the economic development were at their most intense in the Belfort conglomeration itself. By 1911 the territoire's population figure stood at 101,392.
• in the years between 1914 and 1945 the economic narrative was dominated by two world wars and the period of stagnation that came between them. Population declined, having slipped to 86,648 in 1946.
• after 1945 the region became a focus for industrial growth: population levels followed the same rising trend, to stand at 131,999 in 1982. Nevertheless, as in many parts of France, from about 1980 it was clear that the economic crisis of the 1970s was having a lasting effect in slowing the pace of expansion.

Its departmental code is 90, and its prefecture (capital) is Belfort. There is a single arrondissement (Belfort), which is subdivided into 9 cantons and thence into 101 communes.

The president of the Departmental Council is Florian Bouquet, first elected in 2015.

Constituency		Member	Party
	Territoire de Belfort's 1st constituency	Ian Boucard	The Republicans
	Territoire de Belfort's 2nd constituency	Michel Zumkeller	Union of Democrats and Independents

Constituency		Member	Party
	Territoire de Belfort's Senate constituency	Cédric Perrin	The Republicans

• 
  The Lion of Belfort commemorates the resistance of Belfort during the Franco-Prussian War.
• 
  Streets in Belfort
• 
  Cascade of the Savoureuse river
• 
  Eurockéennes music festival

• Communes of the Territoire de Belfort department
• Cantons of the Territoire de Belfort department
• Arrondissement of Belfort

Media related to Territoire de Belfort at Wikimedia Commons

• (in French) Prefecture website
• (in French) Departmental council website
• (in English) Tourist Office website