The destrict as kent the day wis creatit in 1969, durin the reorganization o the destricts in North Rhine-Westphalie, bi mergin Sieg Destrict wi the Destrict o Bonn (frae which Bonn itself wis separatit in 1887 tae become an urban destrict). Sieg Destrict wis creatit in 1825.
Geografically Rhein-Sieg Destrict covers the valley o the river Sieg an anaw, syne the merger wi the Destrict o Bonn, that o the Rhine aroond Bonn, as well an aurie in the maist easterly pairt o the Eifel.
The red lion is the seembol o the dukes o Berg, who awned a lairge pairt o the destrict. The black cross in the shield is the seembol o Cologne, acause anither pairt o the destrict wis awned bi the bishops o Cologne. The yellae sword is the seembol o Saunt Michael, the patron o the michty Michaelsberg Abbey in Siegburg.