| Image Coa: | DEU Niederahr COA.svg |
| Coordinates: | 50.4919°N 7.8611°W |
| Image Plan: | Niederahr im Westerwaldkreis.png |
| State: | Rheinland-Pfalz |
| District: | Westerwaldkreis |
| Verbandsgemeinde: | Wallmerod |
| Elevation: | 300 |
| Area: | 4.03 |
| Postal Code: | 56414 |
| Area Code: | 02602 |
| Licence: | WW |
| Gemeindeschlüssel: | 07 1 43 273 |
| Website: | www.wallmerod.de |
| Mayor: | Jürgen Eulberg[1] |
| Leader Term: | 2019 - 24 |
Niederahr is an Ortsgemeinde – a community belonging to a Verbandsgemeinde – in the Westerwaldkreis in Rhineland-Palatinate, Germany.
The community lies in the Westerwald between Montabaur and Hachenburg. Through the community flows the Ahrbach. The community belongs to the Verbandsgemeinde of Wallmerod, a kind of collective municipality. Its seat is in the like-named town.
In 959, Niederahr had its first documentary mention.
The municipal council is made up of 12 council members who were elected in a majority vote in a municipal election on 13 June 2004.
Right through the community runs Bundesstraße 255, linking Montabaur and Rennerod. The nearest Autobahn interchange is Montabaur on the A 3 (Cologne - Frankfurt), some 5 km away. The nearest InterCityExpress stop is the railway station at Montabaur on the Cologne-Frankfurt high-speed rail line.
Westfalia Separator makes decanters at its Niederahr works.