Guyancourt Population and Area (Yvelines)
Largest city in France 2026: up-to-date figures for Guyancourt (Yvelines)
Guyancourt: Population and Area
With 30,226 inhabitants (INSEE total population in force on January 1, 2026), Guyancourt is the 291st most populous town in France in 2026 and the 14th most populous in the Yvelines department, out of 259 communes. It covers 13 km² (14,438th largest area in France, 43rd largest in the department), with a population density of 2,325 inhabitants per km², or 21 times the national average (110 inhabitants/km²), which ranks it 390th in France for density.
Guyancourt is located in the Yvelines department (78), in the Île-de-France region, where it ranks 105th by population out of 1,266 communes. The most populous town in the Yvelines department is Versailles (85,750 inhabitants); the department is home to 1,508,510 people over 2,284 km².
See the full ranking of communes in the Yvelines department and the regional ranking: largest city in Île-de-France.
Towns of similar size in the Yvelines department: Plaisir (pop. 32,147), Le Chesnay-Rocquencourt (pop. 31,339), Chatou (pop. 31,112), Rambouillet (pop. 28,364), Élancourt (pop. 26,611), Maisons-Laffitte (pop. 23,549).
Sources: INSEE, official population figures in force on January 1, 2026 (total population); areas: IGN / Observatoire des territoires; INSEE code 78297. Rankings are calculated across the 34,858 communes of metropolitan and overseas France in our database.