Grza is a 23km long river in eastern Serbia. It originates from the Rivers Ivanštica (Gornja Grze) and Velika Čestobrodica, between the tourist settlement Grza and the village Izvor. The Grza River is a left tributary of the River Crnica, which flows through Paraćin and west of the city flows into the Great Morava. Upper Grza and its tributaries cut through shorter gorges where relic vegetation is present. The length of the Ivanstica Valley is 11 km and the depth of the gorge is over 300 m, while the length of the meandering gorge is about 2km and the depth is over 250m.
Along Grza and Čestobrodica leads the main road Paraćin - Zaječar, which connects the valleys of Velika Morava and Timok. Along the river and near the spring there are a number of road signs, canopies and benches for tourists and hikers. At the end of the road are several hot springs that form the source of the Grze River. Hot spring of Grza is an exceptional beauty, and the river creates two blue-green ponds and crystal clear water, Lower and Upper Lake. Near the source is the so-called "Tourist Settlement Grza" where there is a hotel, restaurant, hiking home and a large number of holiday homes. Grza is also known as a fishing paradise because it is extremely rich in brook trout and California trout. There are also two footpaths to two sightseeings of Grza.