Bourg-en-Bresse (French pronunciation: [buʁk‿ɑ̃ bʁɛs] ⓘ; Arpitan: Bôrg) is the prefecture of the Ain department in the Auvergne-Rhône-Alpes region in Eastern France.

Bourg-en-Bresse is located at the western base of the Jura Mountains, on the left bank of the Reyssouze, a tributary of the Saône.

In February 1535 it was conquered by France during a full-scale invasion of Savoy, but was restored to Duke Philibert Emmanuel in 1559, when he married Henri II's sister Marguerite.

The duke later built a strong citadel, which afterwards withstood a six-months' siege by the soldiers of Henry IV during the Franco-Savoyard War of 1600–1601.

[4] The Royal Monastery of Brou, named after the suburb settlement of Bourg-en-Bresse in which it lies, is of great artistic interest.

Margaret of Bourbon, wife of Philip II of Savoy, had intended to found a monastery on the spot, but died before her intention could be carried into effect.

The church was actually built early in the 16th century by her daughter-in-law Margaret of Austria, wife of Philibert le Beau of Savoy, in memory of her husband.