Route 21 is a major highway in the United States, primarily located in the state of New Jersey. It runs north-south, connecting various towns and cities, and serves as an important thoroughfare for local traffic. The route is known for its accessibility to residential areas and commercial districts. In addition to its role in transportation, Route 21 is also significant for its proximity to several landmarks, including Branch Brook Park and Newark Liberty International Airport. The highway facilitates travel for commuters and visitors, making it a vital part of the region's infrastructure.