Saint-Genis-Pouilly (; ) is a commune in the Ain department within the Auvergne-Rhône-Alpes region of eastern France.
It is located in the Pays de Gex, at the foot of the Jura Mountains. Bordering the Swiss frontier, it is part of the cross-border area of Geneva. With a population of over 14,000 inhabitants (2023), it is the fifth most populous commune in the department of Ain.
A large portion of CERN, the European laboratory for particle physics, is located within the territory of Saint-Genis-Pouilly; the ALICE experiment is located on the periphery of the town, and the French entrance to the primary CERN campus (Meyrin) and the ATLAS experiment are located only 3 km from the centre of St Genis. CERN is the world's largest fundamental physics research laboratory and its presence has largely been responsible for the development of the community of Saint Genis since the middle of the 1960s.
Geography Saint-Genis-Pouilly is composed of two market towns (Saint-Genis and Pouilly) and two hamlets (Pregnin and Flies). The two market towns have both continued to expand and now practically merge into one, however the two hamlets still remain separate from each other and from the two towns. The elevation of the commune varies from 419 m (at the extreme south of the commune, to the confluence of the rivers Allondon and Nant de l'Ecra) to 502 m (at the extreme north of the commune, in the village of Flies). The commune is situated at the limit between the plains surrounding Geneva and the first foothills of the Jura. As indicated on the map opposite, the communes surrounding Saint-Genis-Pouilly are: Thoiry, Sergy, Crozet, Chevry, Prévessin-Moëns and Satigny (Swiss).
Hydrology Many water courses traverse or border Saint-Genis-Pouilly: Lion, Allondon, Nant de l'Ecra, Bief de la Janvoin, Ouaf, Grand Journans and Petit Journans. In 2005 and 2006, these water courses were subject to a ban on water extraction as a result of the drought. In 2004, only the Allondon and the Lion would have been restricted. The depth of the Allondon is measured at Saint-Genis-Pouilly by a network HYDRO station which transmits these readings by telephone.The readings provided by this station are available here . The record of the height of the Allondon in the medium term is available from the website of the Observatoire départemental de l'Eau .
Climate The meteorological station situated at Geneva International Airport, Cointrin, furnishes measurements of the weather relevant to Saint-Genis-Pouilly. This station is situated only km from the centre of the commune and at a similar elevation ( m).However, because this station is further from the Jura mountains than Saint-Genis-Pouilly it underestimates the rainfall experienced in the commune. In effect, as we can see by consulting the bulletins mensuels|monthly bulletin published by Météo France for the Department of Ain, more rain falls as we move away from the lake and approach the summit of the Jura. Data from this station is available in real time from MétéoSuisse.
Saint-Genis-Pouilly, like the whole of the Pays de Gex and the Canton of Geneva, knows the touch of the Joran, the cold wind which descends towards Lac Léman from the high Jura, where it sometimes provokes a storm.
Natural risks According to a study made in 2002, commissioned by the Department of Agriculture and the Forests of Ain, Saint-Genis-Pouilly is classed in a zone at risk from flooding. According to another official publication, the commune is classed in a zone at risk from torrential downpours and rapid flooding. However, according to the list of major risks to Saint-Genis-Pouilly published on the portal of the website of the Ministry of Ecology, "Prevention of major risks", the commune is classed in a zone at risk from overcrowding from man's activities. These three different qualifications of risk cannot be explained.
Along with the other communes in the canton of Gex, Saint-Genis-Pouilly is classed in seismic zone Ib, which is to say that the seismic risk is low. A new classification is being prepared by the Ministry of Ecology, but it does not seem that this will significantly change the classification of the communes in the Pays de Gex.
Nature zones That part of the Allondon valley which is found within the territory of the commune constitutes a natural zone with interesting ecology, fauna and flora (ZNIEFF type I).ZNIEFF type I are often small zones which present a particular natural interest (e.g. display a protected animal or vegetable species). They assist in the preservation of the biotopes concerned. Further information is available on the site INPN .
The commune is sparsely wooded: the area occupied by forests is 7%.
History It was in 1887 that the current name, Saint-Genis-Pouilly, first appeared on the State civil registers. Previously, Saint-Genis-Pouilly was called Pouilly-Saint-Genis. Before that, the two towns were separately identified. Historically the spelling Saint-Genix had been widely used.
In his historical Atlas, G. Debombourg placed Pulliacum in the epoque of the second reign of the Bourgogne (879-1032) and he placed the church of Pouilly-St-Genis on the religious maps.Debombourg, Georges (1859). Atlas historique du département actuel de l'Ain. Printer: Louis Perrin. In these "Preuves" he cites a text of 993 which mentions Pulliacum.Debombourg, Georges (1859). Atlas historique du département actuel de l'Ain, preuve no 71: "In nomine .. Rodolphus rex ... Pulliacum villam in abbatia Agaunenfe per praecetum concederemus ... hoc donativum fummae pietatis gratia peractum hunc praeceptalem fieri praecipimus ..."
A diary of 1698 mentions a certain Balthazard as a noble of Prengin, in the Pays de Gex (perhaps this is the name given during this epoque to the current hamlet of Pregnin). Between 1601 and 1789 mention is made of the Baronnie of Saint-Genist. Debombourg, Georges (1859). Atlas historique du département actuel de l'Ain, map for the period from 1601 to 1789.
Names of the area with a Gallo-Romanic origin, Polliacum, Pulliacum, derived, with the suffix -acum from the root name Paulius or Pollius.
Towards the end of this time, Saint Genis took on a greater importance. Its takeover of the Postes Royales (next to the current chapel) kickstarted the growth of the town and Pouilly-Saint-Genix soon became Saint-Genis-Pouilly.
Pregnin figures in the Procès-verbaux du Directoire. The name of Saint-Genis, as in the case of Saint-Genis-Laval, probably comes from Saint Genest, a Roman comedian from the second half of the 3rd century, martyred under Diocletian.Other origins have also been suggested. There are many mentions in another encyclopedia .
Roman period The Roman colony Colonia Iulia Equestris founded by Julius Caesar between 50 and 45 BC extended as far as Thoiry and included the territory which was to become Saint-Genis-Pouilly.
The villa of Pouilly had been occupied by a rich family, as evidenced by the jewelry found there.Malgouverne A., Melo A. (1986). Histoire du Pays de Gex - Tome 1 : des origines à 1601. Intersections.
The place called les châtelets, situated to the north of Pregnin took its name, without doubt, from the presence in the 2nd century of a small fort situated on the Roman road running along the Jura.
Middle Ages A priory was established at Pouilly at the end of the 10th century.
In 1301, Uldric, the Seigneur of Saint-Genis renewed his allegiance to the Dauphin.
18th century Cassini's map of 18th century Geneva, based on measurements taken by Calon de Felcourt between 1759 and 1761, shows the town of Pouilly and the hamlets of Pregnin and Flies. A windmill on the site of St Genis can also be identified. The road from Lyon to Geneva and the fork towards Gex are also clearly visible. These roads, easily identifiable by the route they trace through the Pays de Gex, still exist today.
Notable events A few (albeit rather rare) events in the history of the commune : Year Event 1590 The château of Pouilly was destroyed by order of the Conseils.Voir Histoire de Genève depuis son origine, A. Thourel, 1832, Tome 2, p. 338. 1591 The Spanish army of Don Olivaros sacked the Pays de Gex with sword and fire.Voir Histoire de la réunion a la France des provinces de Bresse, Bugey et Gex sous Charles-Emmanuel Ier, J. Baux, ?, p. 338. 1601 As part of the Pays de Gex, Saint-Genis-Pouilly was reattached to France.Restoration of the fiefdom of Saint-Genix by Françoise of Lambert.Voir Histoire politique et religieuse du Pays de Gex ..., J. Brossard, 1831, p. 411; reprise du fief de Farges (auquel le cens de Pouilly est attaché) par Pompée de Gribald (p. 418); mention is also made of the rejoining of the (cens) of Pouilly to the fiefdeom of Flies (p. 418); mention of the rejoining of the (rentes) and (cens) of Saint-Genix to the fiefdom of Sergier (p. 416) but also of Pougny (p. 417) 1662 The Protestant temple of Pouilly was destroyed on 30 November by order of the Evêque of Geneva.Voir Histoire des églises réformées du Pays de Gex, T. Claparède, 1856, p. 130. 1722 The Seigneurie of Saint-Genix was ceded to the Evêque and the Prince of Geneva.La France protestante, E. & E. Haag, 1858, p. 412 1887 First mention of Saint-Genis-Pouilly as the name of the commune.
Today It was the extension within France of CERN (the European Organization for Nuclear Research) in the middle of the 1960s which made Saint-Genis-Pouilly the little town ("coquette")The town received its 2nd flower in 2006 that it is today. It is also thanks to the presence of CERN that the local economy has undergone considerable growth and diversification.
Coat of arms Until recently, the commune used an azure coat of arms with three gold towers. Today, the commune uses exclusively a modern logo which figures prominently on the pages of its website and in its publications.
Population The population of Saint-Genis-Pouilly has grown rapidly since the middle of the 1960s, largely due to the activities of CERN:
One of the consequences of this rapid expansion of the population (along with those of the neighbouring communes in France and Switzerland) is the rapid increase in house prices. For example, the price per square metre of an apartment in the Pays de Gex increased by 59% between 2000 and 2004, according to INSEE.
Its inhabitants are known as Saint-genésiens.
An international population In addition to CERN, the proximity of Switzerland and the international organisations headquartered in Geneva explains why a significant proportion of the population of the commune are foreigners. According to the census taken by INSEE in 2017, the commune contained amongst its inhabitants foreigners (making 35.2%). By way of comparison, the département of Ain contains, also in 2017, amongst its inhabitants foreigners (making 8.7%).
Housing , most housing in Saint-Genis-Pouilly is in apartment blocks (70.9%) and individual houses (27.5%). The apartment blocks are concentrated in the town of Saint-Genis. The commune has a significantly larger proportion of apartments than the other communes in the department: 35.5% of dwellings in Ain are apartments.
The majority of the population in the Pays de Gex, Ain, the Rhône-Alpes region, and mainland France are owner-occupiers of their homes. In Saint-Genis-Pouilly, by contrast, the majority of the population live in rented accommodation (only 46.3% of individual residences are owner-occupied). Within the Pays de Gex, only Ferney-Voltaire has a lower proportion of owner occupiers (39.1%). It is possible that this peculiarity is explained by the large number of employees living in the two communities who work for international organisations.
Administration
Elections The commune is presently administered by Mme S. Durand and her team. The results of the first round of the municipal elections on 15 March 2026 was as follows: