Sempach is a small town in the Swiss canton of Lucerne, built above the eastern shore of Lake Lucerne, and about 11 m. by road north of the Sempach railway station (9 m. N.W. of Lucerne) on the main line between Lucerne and Olten. In 1900 it had 2,592 inhabitants, German-speaking and Romanists; in 2003 it had 3,670.

It has retained some traces of its medieval appearance, especially the main gateway, beneath a watch tower, and reached by a bridge over the old moat. About half an hour distant to the north-east, on the hillside, is the site of the famous battle of Sempach (9 July 1386), in which the Swiss defeated the Austrians, whose leader, Duke Leopold , lost his life. The legendary deed of Arnold of Winkelried is associated with this victory. The spot is now marked by an ancient and picturesque Battle Chapel (restored in 1886) and by a modern monument to Winkelried.

Some miles north of Sempach is the quaint village of Beromünster (973 inhabitants in 1900), with a collegiate church founded in the loth century and dating, in parts, from the nth and i2th centuries (fine 17th-century choir stalls and altar frontals), the chapter of secular canons now consisting of invalided priests of the canton of Lucerne: it was in Beromünster that the first dated book was printed (1470) in Switzerland, by care of the canons, while thence came Gering who introduced printing into France.

See Th. von Liebenau. Die Schlacht bei Sempach (Lucerne, 1886).