Altenkirchen (German pronunciation: [ˈaltn̩ˌkɪʁçn̩] ()) is a district in Rhineland-Palatinate, Germany. It is bounded by (from the north and clockwise) the North Rhine-Westphalian districts Rhein-Sieg, Oberbergischer Kreis, Olpe and Siegen-Wittgenstein, and the districts of Westerwaldkreis and Neuwied.
The district was established in 1816 by the Prussian administration. It combined the county of Wildenburg and the two counties of Sayn. The former had been part of Berg, the latter ones had belonged to the duchy of Nassau.
Altenkirchen is the northernmost district of Rhineland-Palatinate. It is occupied by the northern portions of the Westerwald mountains. The valley of the Sieg River borders the Westerwald on the north. The lands north of the Sieg are called Wildenburgisches Land, after the tiny county of Wildenburg, that once existed here.