The southeastern corner of the former town fortification, the Gunpowder Tower, was built between 1522 and 1532 and was used to store gunpowder. Its external diameter is about 14 m, the inner diameter 8.5 m.

Since the demolition of the town wall in 1885, the tower has stood alone and should in fact have been pulled down long ago to make way for modern traffic needs, particularly as its upkeep had been neglected for years. The Ornithological Association of Zug, founded in 1878, has for many years looked after a colony of swallows (Spyren) which inhabits the tower. The major parts of the tower are maintained by the so-called GAUR (Great, Omnipotent and Invincible Council of Zug). Since 1977 they have carried on the tradition of the previous Great Council, which was disbanded in 1798 when the French army invaded Zug. The Great Council furnished and fitted out the Knights' Chamber and the Council Room on the upper floors.