Mount Arlington occupies a hillside setting along the western shore of Lake Hopatcong in northwestern Morris County. Lake-oriented neighborhoods, marinas, wooded slopes, and a history as a summer destination remain central to the borough’s identity. Interstate 80 and Route 15 provide convenient access to Dover, Roxbury, and other parts of northern New Jersey. Morris County spans north-central New Jersey, combining historic downtowns and suburban employment centers with wooded hills, lakes, farms, reservoirs, and rural western townships. Interstates 80, 287, and 78, together with regional rail lines and major state routes, connect the county with Newark, New York City, and western New Jersey. The relationship between local development and regional access continues to shape the community. Residential streets, civic uses, local businesses, and road connections together shape the community’s physical layout.