The New York City Landmarks Preservation Commission ( LPC ) is the New York City agency charged with administering the city's Landmarks Preservation Law. The Commission was created in April 1965 by Mayor Robert F. Wagner, Jr. following the destruction of Pennsylvania Station the previous year to make way for the construction of the current Madison Square Garden. The Commission is responsible for protecting New York City's architecturally, historically, and culturally significant buildings and sites by granting them landmark or historic district status, and regulating them once they're designated. It is the largest municipal preservation agency in the nation. 
The Landmarks Preservation Commission consists of 11 commissioners, and is required by law to include a minimum of three architects, a historian, a city planner or landscape architect, a realtor and at least one resident of each of the five New York City boroughs. 
According to the Landmarks Preservation Law, a building must be at least thirty years old before the Commission can declare it a landmark. City law also allows for the Commission's decision to be overturned if an appeal is filed within 90 days.
The goal of New York City's landmarks law is to preserve the aesthetically and historically important buildings, structures, and other objects that make up the New York City vista. The Landmarks Preservation Commission is responsible for deciding which properties should be subject to landmark status and enacting regulations to protect the aesthetic and historic nature of these properties. These regulations are generally designed to allow property owners to continue to use and maintain their properties, while preserving the important architectural characteristics of the properties. The commission preserves not only architecturally significant buildings, but the overall historical sense of place of neighborhoods that are designated as historic districts. The commission is responsible for overseeing a range of designated landmarks in all five boroughs ranging from the Fonthill Castle in the North Bronx, built in 1852 for the actor Edwin Forrest, to the 1670s Conference House in Staten Island, where Benjamin Franklin and John Adams attended a conference aimed at ending the Revolutionary War.
The Commission helps preserve the City's landmark properties by regulating changes to their significant features.  The role of the Commission has evolved over time, especially with the changing real estate market in New York City.
The Commission was created in 1965 through groundbreaking legislation signed by the late Mayor Robert F. Wagner in response to the mounting losses of historically significant buildings in New York City, most infamously Pennsylvania Station.
The Landmarks Preservation Commission's first public hearing occurred in September, 1965 over the future of the Astor Library on Lafayette Street in Manhattan. The building was designated a New York City Landmark. Subsequently, the building was adaptively reused as The Public Theater. Twenty-five years later, the Commission was cited by David Dinkins as having preserved New York City's municipal identity and enhanced the market perception of a number of neighborhoods. This success is believed to be due, in part, to the general acceptance of the commission by the city's developers.
In 1989, when the Commission and its process was under review following a panel created by Mayor Koch in 1985, a decision was made to change the process by which buildings are declared to be landmarks due to some perceived issues with the manner by which the Commission operates as well as the realization that the destruction feared when the Commission was formed was no longer imminent.
In its first 25 years of existence, the Commission designated 856 buildings, 79 interiors and 9 parks or other outdoor places as landmarks, while declaring 52 neighborhoods with more than 15,000 buildings as historic districts. As of May 30, 2017, there are more than 36,000 landmark properties in New York City, most of which are located in 141 historic districts in all five boroughs. The total number of protected sites includes 1,398 individual landmarks, 119 interior landmarks and 10 scenic landmarks. Some of these are also National Historic Landmarks (NHL) sites, and many are National Registered Historic Places (NRHP). 
Prominent court decisions
One of the most prominent decisions in which the Commission was involved was the preservation of the Grand Central Terminal with the assistance of Jacqueline Kennedy Onassis.  In 1978, the United States Supreme Court upheld the law in Penn Central Transportation Co., et al. v. New York City, et al., stopping the Penn Central Railroad from altering the structure and placing a large office tower above it. This success is often cited as significant due to the Commission's origins following the destruction of Pennsylvania Station, referred to by some as architectural vandalism.
In 1989, the Commission designated the Ladies' Mile Historic District. The next year marked the first time in the Commission's history that a proposed landmark, the Guggenheim Museum (one of the youngest declared landmarks), received a unanimous vote by the Commission members. The vast majority of the Commission's actions are not unanimous by the Commission members or the community with a number of cases including: St. Bartholomew's Episcopal Church, Bryant Park and a number of Broadway theatres resulting in challenges. One of the most controversial properties was 2 Columbus Circle, which remained at the center of a discussion over its future for a number of years. 
In a heatedly discussed decision on August 3, 2010, the Commission unanimously declined to grant landmark status to a building on Park Place in Manhattan, and thus did not block the construction of Cordoba House. 
South Street Seaport and "New Market Building"
A commission-designated historic district for the South Street Seaport has been active since 1977 and was extended on July 11, 1989. After the Fulton Fish Market relocated to the Bronx in 2005, community members, with leadership from organizer Robert Lavalva, developed the "New Amsterdam Market", a regular gathering with vendors selling regional and "sustainable" foodstuffs outside the old Fish Market buildings. The group's chartered organization planned eventually to attempt to reconstitute the "New Market Building", a 1939 structure with an Art Deco façade  and that was owned by the city, into a permanent food market. However, a real estate company, the Howard Hughes Corporation, possessed a lease for large parts of the Seaport area and desired to redevelop it, generating fears among locals that the New Market Building would be altered or destroyed.  The corporation has offered to provide a more modest food market (at 10,000 sq. ft.) into their development plans, but market organizers have not been satisfied as they believe this proposal is not guaranteed or large enough, and would still not ensure the protection of the historic building. 
A group of community activists formed the "Save Our Seaport Coalition" to advocate that the New Market Building be incorporated into the historic district set by the Landmarks Preservation Commission, in addition to calling for the protection of public space in the neighborhood and for support for the seaport's museum. This group included the Historic Districts Council, the "Save Our Seaport" community group, the New Amsterdam Market, and the Metropolitan Waterfront Alliance. The "Save Our Seaport" group specifically argued that New Market Building was culturally important for its maintenance of the historic fish market for 66 years, and that it offers a "fine example of WPA Moderne municipal architecture (an increasingly rare form throughout the nation)."  They had encouraged others to write letters to the Landmarks Preservation Commission to support formal designation or district protection.  However, in 2013, the Landmarks Preservation Commission declined to hold a hearing to consider this landmark designation or to expand the district.  Community Board 1 supports protecting and repurposing the New Market Building,  and the Municipal Art Society argued in a report that "[it] has both architectural and cultural significance as the last functioning site of the important commercial and shipping hub at South Street Seaport." 
Little Syria and Washington Street
After the September 11 attacks in 2001, New York City tour guide Joseph Svehlak and other local historians became concerned that government-encouraged development in Downtown Manhattan would lead to the disappearance of the last physical heritage of the once "low-rise" Lower West Side of Manhattan.  Also known as "Little Syria" in the late 19th and early 20th centuries, the area between Battery Park and the World Trade Center site, east of West Street and west of Broadway,  had been a residential area for the shipping elite of New York in the early 19th century, and turned into a substantial neighborhood of ethnic immigration in the mid-19th century. In the late 19th and early 20th centuries, centered on Washington Street, the area became well known as Little Syria, hosting immigrants from today's Lebanon, Syria, and Palestine, as well those of many other ethnic groups including Greeks, Armenians, Irish, Slovaks, and Czechs. Due to eminent domain actions associated with the construction of the Brooklyn–Battery Tunnel and the World Trade Center, in addition to significant highrise construction in the 1920s and 30s, only a small number of low-rise historic buildings from the earlier eras remain.
In 2003, Svehlak wrote a manifesto arguing for the landmark designation of "a trilogy"  of three contiguous buildings on Washington Street, the thoroughfare that was most closely associated with "Little Syria." These consisted of the Downtown Community House – which hosted the Bowling Green Association to serve the neighborhood's immigrants – 109 Washington Street (an 1885 tenement), and the terra-cotta St. George's Syrian Catholic Church. After years of advocacy, in January 2009, the Commission held a hearing about the landmark designation of the Melkite church, which did succeed.  However, under Chairman Robert Tierney, the Commission had declined to hold hearings on the Downtown Community House or 109 Washington Street.
Community and preservation groups — including the "Friends of the Lower West Side" and the "Save Washington Street" group led by St. Francis College student Carl "Antoun" Houck — have continued, especially, to advocate for a hearing on the Downtown Community House, arguing that its history demonstrates the multi-ethnic heritage of the neighborhood, and that its Colonial Revival architecture intentionally links the immigrants to the foundations of the country,  and that preserving the three buildings together would tell a coherent story of an overlooked, but important ethnic neighborhood. In addition to national Arab-American organizations,  Manhattan Community Board 1  and City Councilperson Margaret Chin  have also advocated for the Commission to hold a hearing on the Downtown Community House. According to the Wall Street Journal , however, the Commission argues that "the buildings lack the necessary architectural and historical significance and that better examples of the settlement house movement and tenements exist in other parts of the city." The activists have said they hope that the Commission under the new mayor will be more receptive to preservation in the neighborhood. 
- New York City Office of Administrative Trials and Hearings (OATH), for hearings conducted on summonses for quality of life violations issued by the Commission
- List of New York City Landmarks