The Topolog is a river in Dobruja, Romania, a right tributary of the Danube. It rises near the commune of Topolog, in the Casimcea Plateau of Tulcea County forming the Topolog Depression, which divides the Plateau in two parts: the Casimcea Plateau proper and the Hârșova Plateau. Initially, it flows from northwest toward southeast, but eventually, it changes to east-west, spilling into Lake Hazarlâc, which is connected with the Danube. Its length is 50 km (31 mi) and its basin size is 342 km2 (132 sq mi).
The Greci is a small right tributary of the Danube in Romania. It flows into the Danube near Turcoaia. Its length is 13 km (8.1 mi).
The Peceneaga is a river in Romania, right tributary of the Danube. It flows into Lake Peceneaga, which is connected with the Danube, in the village Peceneaga. Its length is 19 km (12 mi).
The Urluia is a right tributary of the Danube in Romania. Its length is 98 km (61 mi) and its basin size is 1,346 km2 (520 sq mi). It passes through Lake Vederoasa and flows into the Danube near Rasova. It flows along the villages Mereni, Miriștea, Osmancea, Ciobănița, Credința, Plopeni, Conacu, Negrești, Curcani, Petroșani, Șipotele, Zorile, Urluia, Aliman and Vlahii.
The Peștera is a right tributary of the Danube in Romania. It flows into the Danube in Cochirleni. Its length is 26 km (16 mi) and its basin size is 257 km2 (99 sq mi).
The Valea Mare is a right tributary of the Danube in Romania. It passes through Lake Dunăreni and flows into the Danube near Dunăreni. Its length is 29 km (18 mi) and its basin size is 344 km2 (133 sq mi).
The Siliștea is a right tributary of the river Țibrin in Romania. It passes through the artificial Lake Domneasca and flows into the Danube near Seimeni. Its length is 21 km (13 mi) and its basin size is 116 km2 (45 sq mi).
The Țibrin is a right tributary of the Danube in Romania. It passes through the artificial Lake Țibrin and flows into the Danube in Seimeni. Its length is 41 km (25 mi) and its basin size is 375 km2 (145 sq mi).
The Dunărea is a right tributary of the Danube in Romania. It flows into the Danube in the village Dunărea. Its length is 23 km (14 mi) and its basin size is 148 km2 (57 sq mi).
The Canaraua Fetei is a right tributary of the Danube in Romania. It passes through Lake Iortmac and Lake Oltina, and flows into the Danube near Oltina. Its length is 16 km (9.9 mi) and its basin size is 181 km2 (70 sq mi).
The Nămolești is a right tributary of the Danube in Romania. It flows into the Danube near Gârliciu. Its length is 20 km (12 mi) and its basin size is 104 km2 (40 sq mi).
The Chichirgeaua is a right tributary of the Danube in Romania. It flows into the Danube near Tichilești. Its length is 17 km (11 mi) and its basin size is 148 km2 (57 sq mi).
The Jidoștița is a small left tributary of the river Danube in Romania. It flows into the Danube in Gura Văii. Its length is 19 km (12 mi) and its basin size is 45 km2 (17 sq mi).
The Mraconia is a small left tributary of the river Danube in Romania. It discharges into the Danube near Dubova. Its length is 19 km (12 mi) and its basin size is 113 km2 (44 sq mi).
The Călmățui is a left tributary of the Danube in Romania. Its source is a few kilometers southwest of Buzău. The 152 km (94 mi) long Călmățui flows generally eastwards and into the Danube at Gura Călmățui. Its basin size is 1,668 km2 (644 sq mi).
The Bahna is a small left tributary of the river Danube in Romania. It discharges into the Danube near Ilovița. Its length is 35 km (22 mi) and its basin size is 137 km2 (53 sq mi).
The Boșneag is a left tributary of the Danube in Romania. It flows into the Danube in Moldova Veche. Its length is 12 km (7.5 mi) and its basin size is 60 km2 (23 sq mi).
The Cocoș is a small river in Constanța County, Romania. It discharges into the northern branch of the Danube–Black Sea Canal in Poarta Albă. Its length is 14 km (8.7 mi) and its basin size is 65 km2 (25 sq mi).
The Medgidia is a small river in Constanța County, Romania. It discharges into the Danube–Black Sea Canal in Remus Opreanu. Its length is 13 km (8.1 mi) and its basin size is 42 km2 (16 sq mi).
The Nisipari is a small river in Constanța County, Romania. It discharges into the Danube–Black Sea Canal near the village Nisipari. Its length is 13 km (8.1 mi) and its basin size is 41 km2 (16 sq mi).
