Castle Clinton or Fort Clinton, once known as Castle Garden, is a circular sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 fort now located in Battery Park at the southern tip of Manhattan Island, New York City

New York City

New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

, in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It is perhaps best remembered as America's first immigration station (predating Ellis Island

Ellis Island

Ellis Island in New York Harbor was the gateway for millions of immigrants to the United States. It was the nation's busiest immigrant inspection station from 1892 until 1954. The island was greatly expanded with landfill between 1892 and 1934. Before that, the much smaller original island was the...

), where more than 8 million people arrived in the U.S. from 1855 to 1890. Over its active life, it has also functioned as a beer garden

Beer garden

Beer garden is an open-air area where beer, other drinks and local food are served. The concept originates from and is most common in Southern Germany...

, exhibition hall, theater, public aquarium

Public aquarium

A public aquarium is the aquatic counterpart of a zoo, housing living aquatic species for viewing. Most public aquariums feature tanks larger than those kept by home aquarists, as well as smaller tanks. Since the first public aquariums were built in the mid-19th century, they have become popular...

, and finally today as a national monument

U.S. National Monument

A National Monument in the United States is a protected area that is similar to a National Park except that the President of the United States can quickly declare an area of the United States to be a National Monument without the approval of Congress. National monuments receive less funding and...

.
Today, Castle Clinton stands approximately two blocks west of where Fort Amsterdam

Fort Amsterdam

For the historic fort on the island of Saint Martin, see Fort Amsterdam Fort Amsterdam was a fort on the southern tip of Manhattan that was the administrative headquarters for the Dutch and then British rule of New York from...

 stood almost 400 years ago, when New York City was still known by the Dutch name New Amsterdam

New Amsterdam

New Amsterdam was a 17th-century Dutch colonial settlement that served as the capital of New Netherland. It later became New York City....

.

Construction began in 1808 and was completed in 1811.