"Eminent domain" (also called "condemnation") is the power of government agencies to acquire property for "public use" so long as the government pays "just compensation." Recognized public uses for which the power of eminent domain may be used include, among other things, schools, parks, roads, highways, subways, fire and police stations, public buildings, and the elimination of blight through redevelopment. A key attribute of eminent domain is that the government can exercise its power of eminent domain even if the owner does not wish to sell his or her property. 

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http://www.eminentdomainlaw.net/propertyguide.html