TIRLEMONT (Flem. Tkienen), a town of Belgium, in the province of Brabant, 29 1 miles by rail to the east of Brussels, on the Great Geete. The old walls, dismantled since 1804, are nearly 6 miles in circuit, but enclose a large extent of arable and garden ground. The streets are regular, and there are some spacious squares; the market-place contains the town-hall, recently restored, and the church of Notre Dame du Lac, founded in 1298, enlarged in the 15th century, but still unfinished. The church of St Germain dates partly from the 9th century. The industries of the place include the making of steam-engines, brewing, distilling, soap-making, tanning, and various woollen and cotton manufactures. The population in 1876 was 13,296.

Tirlemont was once a much larger and more flourishing town than it now is; it has suffered much in war and was taken by the French in 1635, by Marlborough in 1705, and again by the French in 1793. John Bolland, the famous editor of the Acta Sanctorum, was born here in 1596.