IEEE has just announced a new Wireless standard 802.22 that can cover up to 12,000 square miles. The standard is actually for Wireless Regional Area Networks or WRAN which uses the white spaces left in the TV frequency spectrum.
This new wireless standard is expected to bring internet connectivity to large areas which are less densely populated that did not have coverage previously. The WRAN will be able to deliver up to 22 Mbps without interfering with existing TV broadcast stations.
http://www.tekgoblin.com/2011/08/01/wifi-8...0-square-miles/