The Linnaisten swamp is a protected ombrotrophic raised bog area in Lahti area. Total conservation area is 200 hectares. It is a sample of Päijä-Häme's bog nature. The area is surrounded by forests and its' peat thickness is about three meters. There are duckboards built over the bog, that are recommended to be used when moving in the bog.
The Linnaisten swamp conservation area was formed to save representative sample of Päijä-Häme's bog nature. Most of the bogs in Lahti region have been ditched and taken into forestry use. Linnaisten swamp was also ditched before in 1982 it was pacified. Majority of the nature values remained. First 100 hectares were pacified and later in 2003 another 100 hectares were joined to the conservation area. Due to this the conservation area is 200 hectares today.
The Linnaisten swamp was approved to European Union's Natura 2000 -network in 1998 as a representative sample of southern Finland's ombrotrophic raised bog nature. The aim of Natura 2000 is to secure nature types' and species' habitat which are defined in the EU's nature directive.