In the papal conclave held from 14 to 16 June 1846, Giovanni Maria Mastai Ferretti, Bishop of Imola, was elected on the fourth ballot to succeed the recently deceased Gregory XVI as pope. He took the name Pius IX. Of the 62 members of the College of Cardinals, 52 assembled in the Quirinal Palace, one of the papal palaces in Rome and the seat of two earlier 19th century conclaves. The conclave was the last to elect a ruler of the Papal States, the extensive lands around Rome and Northern Italy which the Catholic Church governed until 1870.

The Quirinal Palace is an historic building in Rome, Italy, one of the three current official residences of the President of the Italian Republic, together with Villa Rosebery in Naples and the Tenuta di Castelporziano, an estate on the outskirts of Rome, some 25 km from the centre of the city. It is located on the Quirinal Hill, the highest of the seven hills of Rome in an area colloquially called Monte Cavallo. It has served as the residence for thirty popes, four kings of Italy and twelve presidents of the Italian Republic.