Le Tréhou (French pronunciation: [lə tʁeu]; Breton: An Treoù-Leon) is a commune in the Finistère department of Brittany in north-western France.

Inhabitants of Le Tréhou are called in French Tréhousiens.

Historical population

Year Pop. ±% p.a. 1793 1,077 —     1800 1,054 −0.31% 1806 1,068 +0.22% 1821 1,045 −0.15% 1831 1,072 +0.26% 1836 1,106 +0.63% 1841 1,120 +0.25% 1846 1,184 +1.12% 1851 1,169 −0.25% 1856 1,169 +0.00% 1861 1,172 +0.05% 1866 1,213 +0.69% 1872 1,163 −0.70% 1876 1,272 +2.26% 1881 1,198 −1.19% 1886 1,228 +0.50% 1891 1,167 −1.01% 1896 1,134 −0.57%	Year Pop. ±% p.a. 1901 1,046 −1.60% 1906 1,027 −0.37% 1911 1,084 +1.09% 1921 1,061 −0.21% 1926 1,003 −1.12% 1931 926 −1.58% 1936 856 −1.56% 1946 774 −1.00% 1954 671 −1.77% 1962 619 −1.00% 1968 596 −0.63% 1975 527 −1.74% 1982 453 −2.14% 1990 395 −1.70% 1999 408 +0.36% 2007 522 +3.13% 2012 609 +3.13% 2017 633 +0.78%
Source: EHESS and INSEE (1968-2017)

• List of the works of Bastien and Henry Prigent
• Communes of the Finistère department
• Le Tréhou Parish close

• Official website (in French)
• Base Mérimée: Search for heritage in the commune, Ministère français de la Culture. (in French)
• Mayors of Finistère Association (in French)