The patroness of Niscemi is Maria Santissima del Bosco, and the summer patronal feast traditionally falls on the second Sunday of August: on the first Sunday of the month the image is carried in procession from the sanctuary to the mother church, and in the following days the main religious and civic celebrations take place. There is also a second cycle of celebrations, the so-called month of the Madonna, traditionally between 21 April and 21 May, tied to the memory of the image's finding, with pilgrimages between the sanctuary and the mother church.
The devotion goes back to 1599, the year tradition places the finding of the image of Maria Santissima del Bosco. The original painting was lost in a fire in 1769, while it was in the mother church; the sanctuary today keeps a copy of it. The present building was built between 1749 and 1758, under the direction of Silvestro Gugliara, on the site of an earlier chapel destroyed by the 1693 earthquake: it has a single elongated elliptical nave and a sober Baroque façade. Below the church lies the chapel of the Acqua Santa, with the well tradition ties to the finding of the image, also used as a baptistery since 1998.
