Area code 551 is an overlay for area code 201 in northeastern New Jersey, including Jersey City, Hoboken, and much of Bergen and Hudson Counties. Introduced in 2001, it was created to handle increasing demand in one of the most densely populated and economically active parts of the country. The area is tightly connected to New York City and plays a vital role in finance, media, and transportation. Ten-digit dialing is required. While 201 holds legacy prestige, 551 is now firmly established and reflects the constant growth and urban dynamism of northern New Jersey.