The Idar Forest (German: Idarwald, Celtic: "id ar" - hill forest above the land) is part of the Hunsrück low mountain range in the German federal state of Rhineland-Palatinate, Germany.

The Idar Forest lies in the districts of Bernkastel-Wittlich and Birkenfeld in the northeast of the Saar-Hunsrück Nature Park. It lies more or less in the triangle formed by the villages of Morbach (in the northwest), Rhaunen (northeast) and Idar-Oberstein (southeast), but apart from Morbach – does not extend as far as these places. The underlying rocks are primarily made up of Lower Devonian quartzites.

Amongst the highest mountains in the Idar Forest are:

• An den zwei Steinen (766 m)
• Kahlheid (766 m)
• Steingerüttelkopf (757 m)
• Ruppelstein (755 m)
• Idarkopf (746 m) - crowned by the Idarkopf Tower
• Usarkopf (724 m)

The following streams rise in, or on the edge of, the Idar Forest:

• Dhron
• Idarbach (Nahe) - rises between Erbeskopf and Kahlheid
• Idarbach (Hahnenbach) - rises north of the Idarkopf near Hochscheid
• Rhaunelbach
• Steinbach

The following lakes and reservoirs are located in, or on the edge of, the Idar Forest:

• Steinbach Reservoir on the Steinbach

• Uwe Anhäuser: Heimat am Idarwald. Literaturverlag Dr. Gebhardt und Hilden, Idar-Oberstein 2001, ISBN 3-932515-30-7.

• Idarkopf