R-2 zoning refers to a traditional zoning category in which apartment complexes are permitted to be constructed along with dwellings and duplexes. This category differs from R-1 zoning by including multifamily buildings. The traditional R-1, R-2, and C-1 zoning structure, also referred to Euclid or pyramid zoning, was upheld by a landmark 1926 U.S. Supreme Court decision, but is no longer in widespread use.
Zoning laws permit the enforcement of land use and construction policies, and they are used by local governments in many countries. Their primary purpose is to prevent land use that might be incompatible with existing uses. Procedures to apply for exceptions to zoning laws, known as variances, can be found in many municipalities. The varied approaches to zoning regulations fall under the broad categories of Euclidean, performance, form based and incentive.