In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Q: Which enclaves are quickly gaining mass?, Context: Although sizable Orthodox Jewish communities are located throughout the United States, many American Orthodox Jews live in New York State, particularly in the New York City Metropolitan Area. Two of the main Orthodox communities in the United States are located in New York City and Rockland County. In New York City, the neighborhoods of Borough Park, Midwood, Williamsburg, and Crown Heights, located in the borough of Brooklyn, have particularly large Orthodox communities. The most rapidly growing community of American Orthodox Jews is located in Rockland County and the Hudson Valley of New York, including the communities of Monsey, Monroe, New Square, and Kiryas Joel. There are also sizable and rapidly growing Orthodox communities throughout New Jersey, particularly in Lakewood, Teaneck, Englewood, Passaic, and Fair Lawn.
A:
in Rockland County and the Hudson Valley of New York