The river Hron flows through the Žiar basin and at the same time through the town of Žiar nad Hronom. The length of the middle course of the Hron is about 60 km. The most important tributary on the right is the Lutilský stream, which flows into the Hron near the town in front of Šibeniční vrch. The length of the stream is 19 km.
The Žiar basin, in which Žiar nad Hronom lies, as well as the surrounding villages, has an area of about 109 km2. It is surrounded by promontories of relatively high mountains: Vtáčnik (1346 m above sea level), Kremnické vrchy (Suchá Hora 1232 m above sea level) and Štiavnické vrchy (Sitno 1010 m above sea level). The altitude of the town at the railway station on the left bank of the Hron is 243.73 m above sea level
The territory of the Žiar basin belongs to the West Carpathian volcanic arch. It lies in Central Slovak Neogene volcanic formations. It is a tectonic depression between the surrounding mountains. Its filling is formed by powerful layers of tuffites, clays and conglomerates with thin coal inserts. The surrounding hills and mountains are built of rhyolites, andesites and basalts. The Hrona floodplain is made of gravel, sand, clay and sloping rubble.
Žiarska kotlina lies in a warm, slightly humid area with a mild winter. The average annual rainfall is approximately 700 mm, evaporation 450 - 500 mm. The average annual temperature is 8 - 9 C °. The surrounding forests are mostly beeches with mixed spruce or pine, in some localities there is also winter oak or maple.
Žiarska kotlina does not have a special animal, but there are almost all species of animals and birds of central Slovakia. Special attention deserves breeding and fishing in the dead arm of the river Hron. After completing the regulation of the Hron River, the Fishermen's Association established a pond in the dead arm from 1960. The main farmed fish are carp, pike and toothfish. Muskrats, otters, wild ducks and wild chickens also live here. Water flows into the pond below Hron from the Lutilský stream.