Recognizing the need to identify and protect neighborhoods with distinct architectural and cultural resources, the City has developed an expansive program of Historic Preservation Overlay Zones (HPOZs). HPOZs, commonly known as historic districts, provide for review of proposed exterior alterations and additions to historic properties within designated districts. The City Council adopted the ordinance enabling the creation of HPOZs in 1979; Angelino Heights became Los Angeles’ first HPOZ in 1983. Today, the City of Los Angeles has 29 designated HPOZs, with many more under consideration (Proposed HPOZs). HPOZ areas range in size from neighborhoods of approximately 50 parcels to more than 3,000 properties. While most districts are primarily residential, many have a mix of single-family and multi-family housing, and some include commercial and industrial properties. HPOZs are established and administered by the Los Angeles City Planning Department (in concert with the City Council). Individual buildings in an HPOZ need not be of landmark quality on their own: it is the collection of a cohesive, unique, and intact collection of historic resources that qualifies a neighborhood for HPOZ status.