The river that forms a boundary between Paraguay and Brazil is Iguazu River. The river is quite large and it also forms a boundary between Brazil and Argentina.
The Mississippi River forms the eatern border. The St. Frances River form a small part of the border on the northeast. The Red River forms a small part of the southwestern border.
the northeast border of texas is the red river
The Mississippi River forms the boundary between Illinois and Missorui
The Ohio River forms the boundary between Indiana and Kentucky.
The Columbia River forms most of the Washington/Oregon boundary
The Ohio River forms the boundary between Indiana and Kentucky.
Missouri river
The Mississippi River forms the eatern border. The St. Frances River form a small part of the border on the northeast. The Red River forms a small part of the southwestern border.
The Missouri River flows through Northeast Kansas
The Potomac river
The Danube River forms part of the boundary between Bulgaria and Romania.