Yonkers is the fourth largest city in the U.S. State of New York (it falls behind New York City, Buffalo, and Rochester), and the largest city in Westchester County, with a population of 196,086 (according to the 2000 census). More recent estimates put the population at 197,234 in 2002, 197,126 in 2004 and 196,425 in 2005. Yonkers borders the New York City borough of The Bronx and is 2 miles (3 km) north of Manhattan at the cities' two respective closest points.

The city is home to several attractions, an example of which is Yonkers Raceway, a harness racing track that has renovated its grounds and clubhouse and added legalized video slot machine gambling in 2006 in a "racino" called Empire City. There is also a large shopping area along Central Park Avenue (NY 100), informally called "Central Avenue" by area residents, a name it takes officially a few miles north in White Plains, New York. Yonkers is located at 40° 56' 29" N, 073° 51' 52" W.

The land on which the city is built was once part of a 24,000 acre (97 km²) land grant that ran from the current Manhattan/Bronx border at Marble Hill northwards for 12 miles (19 km), and from the Hudson River eastwards to the Bronx River. This grant was given in July 1645 by New Netherland Director-General Willem Kieft to Adriaen van der Donck, originally named Colen Donck. Van der Donck was known locally as the Jonkheer or Jonker (etymologically, "young gentleman"; in effect, "Esquire"), a word from which the name "Yonkers" is directly derived. Van der Donck built a saw mill near where the Nepperhan Creek met the Hudson; the Nepperhan is now also known as the Saw Mill River.

Near the site of van der Donck's mill is Philipse Manor Hall, a Colonial-era manor house which today serves as a museum and archive, offering many glimpses into life before the American Revolution. The original structure (later enlarged) was built around 1682 by Frederick Philipse, a wealthy Dutchman who, by the time of his death, had amassed an enormous estate which encompassed the entire modern City of Yonkers, as well as several other Hudson River towns. Philipse's great-grandson, Frederick Philipse III, was a prominent Loyalist during the American Revolution, who, because of his political leanings, was forced to flee to England.

For its first two hundred years, Yonkers was a small farming town with an active waterfront. Yonkers's later growth rested largely on developing industry. In 1853, the Otis Elevator Company, opened the first elevator factory in the world on the banks of the Hudson. Around the same time, the Alexander Smith and Sons Carpet Company (in the Saw Mill River Valley) expanded to 45 buildings, 800 looms, and over 4,000 workers and was known as one of the premier carpet producing centers in the world. In 1892, Smith carpets were sent to Moscow for the czar's coronation. Bakelite, the first completely synthetic plastic, was invented in Yonkers circa 1906, and manufactured there until the late 1920s.

Early in the 20th Century, Yonkers also hosted a brass era automobile maker, Colt Runabout Company; despite the car's seemingly glowing performance, the company went under.

Yonkers was also the headquarters of the Waring Hat Company, at the time the nation's largest hat manufacturer. World War II saw the city's factories manufacture such items as tents and blankets in the Alexander Smith and Sons Carpet Factory and tanks in the Otis Elevator factory.

After World War II, however, with increased competition from less expensive imports, Yonkers lost much of its manufacturing activity. The Alexander Smith Carpet mill fell on hard times and ceased operation on June 24, 1954. In 1983, the Otis Elevator Factory finally closed its doors. With the loss of jobs in the city itself, Yonkers followed the trend of many suburban cities after World War II, becoming primarily a commuter city. Yonkers' excellent transportation infrastructure, including three commuter railroad lines (now two) and five parkways and freeways, as well as its 15-minute drive from Manhattan, made it a desirable city to live in. Yonkers' manufacturing sector, however, has recently shown a resurgence. A Kawasaki railroad cars assembly plant opened in 1986 in the former Otis plant, producing the new R142A and R160B cars for the New York City Subway, and the PA4 and upcoming PA5 series for PATH.

Aside from being a manufacturing center, Yonkers also played a key role in the development of entertainment in the United States. In 1888, Scottish immigrant John Reid founded the first golf course in the United States, St. Andrew's Golf Club, in Yonkers. On January 4, 1940, Yonkers resident Edwin Howard Armstrong transmitted the first FM radio broadcast (on station W2XCR) from the Yonkers home of C.R. Runyon, a co-experimenter. Yonkers also had the longest running pirate radio station, owned by Allan Weiner during the 70s through the 80s. In spite of this historic broadcast, Yonkers has the dubious distinction of being the largest city in the United States to not have a broadcast station licensed to it, but WVIP / WRTN 93.5 FM has been in Yonkers, NY since the 1950s. One of the main reasons for this is its central location in the New York City market, with many nearby stations crowding the airwaves.

The Irish-American community plays a prominent role in Yonkers, and the city hosts one of the oldest St. Patrick's Day parades in the country.

The city is also home to a large Italian-American community, many of whom moved to the city after originally settling in the Bronx and in Brooklyn. The city hosts a large Columbus Day festival with a Miss Italian-American pageant.

There also once was a significant Jewish population (the Broadway plays Hello Dolly! and Lost in Yonkers both take place within the Yonkers Jewish community). However, its size has dwindled (but not vanished) as the older generation dies off and the younger generation moves to the Sunbelt or to other (usually more affluent) parts of metropolitan New York City, with the trend accelerating after the housing integration court battles. However, in recent years, some areas bordering similar neighborhoods in Riverdale are seeing an influx of Orthodox Jews.

There was a years-long battle over housing integration in the 1980s and 1990s, which ended only after a court ruling nearly bankrupted the city government, by imposing exponentially increasing contempt of court penalties after the then-mayor refused to build public housing outside of the traditionally black and Latino neighborhoods downtown.