Staten Island was named in honor of the States General in the Netherlands, but an alternative joke etymology spread in the 1930s and 1940s and is still told. The Dutch explorers came into New York harbor and spotted land. They asked themselves:
 
“‘s dat en island?” (“Is that an island?”)
     
   
Wikipedia: Staten Island
Staten Island (pronounced /ˌstætənˈaɪlənd/) is a borough of New York City in the southwest part of the city. Staten Island is separated from New Jersey by the Arthur Kill and the Kill Van Kull, and from the rest of New York by New York Bay. With a population of 487,407, Staten Island is the least populated of the five boroughs but is the third largest in area at 59 sq mi (153 km2).
 
The Borough of Staten Island is coextensive with Richmond County, the southernmost county in the state of New York. Until 1975, the borough was officially named the Borough of Richmond. Staten Island has been sometimes called “the forgotten borough” by inhabitants who feel neglected by the city government.
 
Staten Island is overall the most suburban of the five boroughs of New York City. The North Shore, especially the neighborhoods of St. George, Tompkinsville, Park Hill, and Stapleton, is the most urban part of the island; it contains the officially designated St. George Historic District and The St. Paul’s Avenue-Stapleton Heights Historic District, which feature large Victorian homes. The South Shore has more suburban-style residential neighborhoods and is home to the two and one-half mile long F.D.R. Boardwalk, the fourth longest in the world. Historically, the central and southern sections of the island were once dominated by dairy and poultry farms, almost all of which disappeared in the 20th century.
 
The borough is accessible to Brooklyn via the Verrazano-Narrows Bridge and to New Jersey via the Goethals Bridge, Outerbridge Crossing, and Bayonne Bridge. Staten Island has Metropolitan Transportation Authority (MTA) bus service and an MTA rapid transit line, the Staten Island Railway, which runs from the ferry terminal at St. George to Tottenville. The free Staten Island Ferry connects the borough to Manhattan and is a popular tourist attraction, providing views of the Statue of Liberty, Ellis Island and lower Manhattan.
 
New York Public Library - Staten Island History Tour
The name Staten Island was given in honor of the States General in the Netherlands which sponsored the settlement of New Amsterdam. When the British took over New Amsterdam in 1664, Staten Island’s name was changed to Richmond and we became among the first 10 counties of New York State in 1683. Today both names, Staten Island and Richmond, are used interchangeably.
     
Google Books
Progressive Architecture
Edited by Eugene Clute, Russell Fenimore Whitehead, Kenneth Reid, Elizabeth L. Cleaver
v. 28 - 1947
Pg. 100:
Although George R. Stewart omitted the familiar and dubious tale of how Staten Island, New York, was named (said one Dutchman to another: Iss dat en island?).
   
Google Books
Ambassador’s Wife
By Jean Spender
Sydney: Angus and Robertson
1968
Pg. 190:
“How do you say it got its name?” “Well,” said Percy, “when the Dutch first sailed into what is now the port of New York, one of the officers on the bridge, spying this piece of land through the morning mists, inquired, “Ist dat an island?”
   
10 January 1969, Naugatuck (CT) Daily News, pg. 4, col. 6:
IF YOU GET a chance, ask Russ Sumpf how Staten Island got its name…it has something to do with a thick Dutch accent of Peter Stuyvesant.
     
Google Books
Low Man Rides Again
By Harry Allen Smith
Garden City, NY: Doubleday
1973
Pg. 104:
David Snell, a writer friend of mine, once asked me if I knew how Staten Island got its name. I didn’t. He said that when Henry Hudson sailed the Half Moon up the Lower bay of New York he pointed to the shoreline on the west and said to his spyglass-holder: “‘s dat an island?”
 
Google Books
Pulpsmith
By Generalist Association (U.S.)
v. 3 - 1983
Pg. 124:
...recalled a Staten Island joke from his school days. Know how Staten Island got its name? Peter Minuet was standing at the tip of Manhattan. He saw something across the water and asked: “S ‘tat ‘n Island?” Watcha laughin’ at, Dad?
     
Democratic Underground
CO Liberal
Tue Aug-24-04 02:34 PM
How Staten Island Got Its Name
In 1609, Henry Hudson was sailing up the river that now bears his name. He sees a large land mass to his left, points to it, and says to his first mate - “Hey!! ‘stat an island??”
 
Bar-Ump-Pump!!! *** cymbal crash ***
 
Thank you, thank you…I’ll be here all week.
     
New York City Metblogs
The Things You Never Really Do: A Photo Essay
By nyc_anna March 12th, 2006 @ 2:59 PM
(...)
COMMENTS
Ian Canino (unregistered) on March 12th, 2006 @ 5:07 pm
Haha.. Nice photo-essay. Ever heard of how Staten Island got its name? A couple of dutch settlers left the southern tip of Manhatten and in the fog they saw the island. One of the settlers said in english with a dutch accent “Ez dat en island?”
 
I believe it is a urban legend but totally possible!
     
Staten Island Genealogy Blog
“Is dat an eyelandt?” How Staten Island Got Its Name
August 13, 2008 by statenislandgenealogy
It’s like this… Henry Hudson, the English explorer who convinced the Dutch government to finance his trip to the New World in 1609, was finally approaching land after months at sea. Henry, who despite his European heritage had an unexplainable Brooklyn accent, was notified of a land sighting by his men. Looking through the primitive eyeglass of the day, he said with excitement, “Is dat an Eyelandt?!!!”
 
No. Just kidding.
 
TonyP4 Jokes, Satires, Pictures…
Wednesday, February 18, 2009
How Staten Island got its name
When the English captain Henry Hudson was exploring the area around what would become New York for the first time, the fog had rolled in and his Dutch first mate was peering through it. He made out a shape in the distance and asked the captain in broken English, “Is dat an’ island?” Hudson thought he said “Staten Island” and so the name stuck.