The total length of Long Island is 118 miles (190 kilometers). It is 23 miles (37 kilometers) wide from south to north. Not including Brooklyn and Queens, it is 103.5 miles (166.6 kilometers) long. The total length of Long Island is 118 miles (190 kilometers). It is 23 miles (37 kilometers) wide from south to north.<br /><br />Not including Brooklyn and Queens, it is 103.5 miles (166.6 kilometers) long.