Riddarhyttan is a locality in Skinnskatteberg Municipality, Västmanland County, Sweden with 431 inhabitants in 2010. It has an old iron mining tradition, which can be followed back to the last centuries before Christ, the last mine was closed down in 1979. Riddarhyttan is, along with Skinnskatteberg, one of only two urban areas or localities (more than 200 inhabitants) in the Skinnskatteberg Municipality in the western part of Västmanland County, on the border to Örebro County.
It is located in the north of the historical province of Västmanland. The area of the locality, as defined by Statistics Sweden, is 1.5677 km2. The Swedish national road 68 is running through Riddarhyttan and the lake Lien is located next to it. It lies in the middle of the historically mining district Bergslagen. It is about 30 km to Fagersta, 35 km to Lindesberg and 70 km to Västerås.
When the last ice age in Bergslagen came to an end about 9500 years ago, Riddarhyttan was located on the border between land and sea. That resulted in kettles, glacial erratics and other specific landforms. When the ice was melting, iron was released from the bedrock into the groundwater and became exposed iron oxide (ochre). That gave rise to a red-colour soil in some parts of Riddarhyttan, especially in the area called Röda Jorden (red earth).