Saint-Germain-en-Laye is a commune in the western suburbs of Paris in France. It is located 19.1 km (11.9 miles) from the center of Paris. Inhabitants are called Saint-Germanois. With its elegant tree-lined streets it is, with Garches-Vaucresson, the poshest suburb of Paris, combining both high-end leisure spots and ultra-residential neighborhoods (see the Golden Triangle of the Yvelines). It is a sous-préfecture of the Yvelines département, being the seat of the Arrondissement of Saint-Germain-en-Laye. Because it includes the National Forest of Saint-Germain-en-Laye, it covers approximately 48 km², making it the largest commune in Yvelines. It occupies a large loop of the Seine. Saint-Germain-en-Laye lies at one of western terminus of the line A of the RER.