As of today, Verizon Wireless, AT&T and Sprint have been at the vanguard of the LTE expansion in the US. However, Verizon Wireless maintains a significant lead in the number of markets covered. The company has disclosed that it now offers LTE service in 196 markets, while AT&T is behind with 28 markets. Sprint is still trying to expand its LTE network, which will not officially begin until this summer. It expects to have 6 major LTE cities up before the end of the year.
Below is the map showing the expected launches of new LTE networks per service provider in 2012. Verizon is represented by the red icon, AT&T by the blue and Sprint by the yellow.
View Q1 2012: New LTE in the USA in a larger map