Saint-Germain-en-Laye (French pronunciation: [sɛ̃ ʒɛʁmɛ̃ ɑ̃ lɛ]) is a commune in the Yvelines department in the Île-de-France in north-central France. It is located in the western suburbs of Paris 19.1 km (11.9 mi) from the centre.
Inhabitants are called Saint-Germanois. With its elegant tree-lined streets it is one of the wealthiest suburbs of Paris, combining both high-end leisure spots and exclusive residential neighborhoods (see the Golden Triangle of the Yvelines).
Saint-Germain-en-Laye is a sub-prefecture of the department. Because it includes the National Forest of Saint-Germain-en-Laye, it covers approximately 48 km2 (19 sq mi), making it the largest commune in the Yvelines. It occupies a large loop of the Seine. Saint-Germain-en-Laye lies at one of the western termini of Line A of the RER.