The new city is predominantly a large suburban residential area where most houses have been built in the second half of the 20th century, although it treasures some older historical districts. For instance, the historical sector of Vieux-Longueuil was designated a heritage site by the municipality in 1993 and contains over 450 buildings built before 1945, including the remarkable St Mark's Anglican church (1842) and the Saint-Antoine Roman Catholic cathedral (1885). The boroughs of Boucherville, Saint-Lambert and Saint-Bruno-de-Montarville also display many historically significant buildings.
Longueuil has a large commercial sector with numerous regional or local shopping centres, and boulevard Taschereau lined with stores and restaurants. It also boasts a diversified industrial base with a significant aerospace industry. Pratt & Whitney and Héroux-Devtek are the leading enterprises in that sector.
Most of Montréal's universities have established teaching facilities near the Longueuil metro station. UNIVERSITÉ DU QUÉBEC à Montréal was the first university (1980) to offer courses and continuing education with its Centre d'études universitaires de la Montérégie. It was followed by the UNIVERSITÉ DE SHERBROOKE (1989), the UNIVERSITÉ DE MONTRÉAL (1999) and MCGILL UNIVERSITY (2003). Established in 1969 by succeeding the Externat classique of Longueuil, the Collège Edouard-Montpetit is one of the first CÉGEPs in Québec. Champlain Regional College has been established in the borough of Saint-Lambert since 1971. Longueuil houses the Théâtre de la Ville, a centre for performing arts that features 2 theatres. A weekly regional newspaper, Le Courrier du Sud, and a community radio station, CHAA-FM, provide the South Shore's inhabitants with information and entertainment.