Rimava is a river in southern central Slovakia, which flows only in the Rimavská Sobota District. It is a right tributary of the Slaná river. The Rimava is 83 km long and its basin size is 1,378 km. Its source is in Veporské vrchy at approximately 1,130 m above sea level. It flows through the towns of Tisovec, Hnúšťa and Rimavská Sobota before merging i…Rimava is a river in southern central Slovakia, which flows only in the Rimavská Sobota District. It is a right tributary of the Slaná river. The Rimava is 83 km long and its basin size is 1,378 km. Its source is in Veporské vrchy at approximately 1,130 m above sea level. It flows through the towns of Tisovec, Hnúšťa and Rimavská Sobota before merging into the Slaná river near Vlkyňa at 145 m a.s.l.