Police say a 27-year-old woman, who barricaded herself in a house with a rifle, is a member of the Armed Forces and may be depressed.
Police evacuated 20 nearby homes as a precaution, while other neighbours were ordered to stay indoors.
Local officers in Saint-Jean-sur-Richelieu -- about 40 kilometres southeast of Montreal -- received a call Wednesday afternoon about a woman inside a home on Beaulieu Street.
When police arrived, the woman would not answer the door or cooperate.
Quebec's provincial police force was called in to assist.
The siege ended after 6 p.m. when police entered the home, and transported the woman to hospital.