Kaser is a village in the Town of Ramapo, Rockland County, New York, United States. The village is completely surrounded by the Hamlet of Monsey, and borders it at all ends. As of the United States 2010 Census, the village population was 4,724.
Kaser is a village with a population consisting almost entirely of Hasidic Jews of the Viznitz sect. The etymology of the name is derived from the Eastern European pronunciation of Hebrew, as the word "כֶּתֶר" is pronounced "Kay-ser", hence "Kaser", (כֶּתֶר=crown in English). A total of 4% of Kaser's population claims Romanian ancestry, making Kaser the most Romanian census place in the United States.
The village is the most densely populated municipality in New York State according to the 2010 census, being the only incorporated place in the state with a higher population density than New York City; and the 5th most in the United States.