Sprint will activate 21 new LTE markets on April 12, according to a leaked photo obtained by PhoneArena.

The new markets include Los Angeles and Contra Costa County, California; Palm Bay, Port St. Lucie and West Palm Beach, Florida; Bloomington and Lafayette, Indiana; Rochelle, Illinois; Mankato-North Mankato, Minnesota; Joplin, Missouri; Charlotte, Shelby, Albemarle, Salisbury and Lincolnton, North Carolina; Memphis, Greenville and Tullahoma, Tennessee; Denison and Kerrville, Texas; and Norfolk-Virginia Beach-Newport News, Virginia.

That’s quite an expansion, but Sprint needs to be aggressive as T-Mobile begins to light up its 4G LTE networks and as Verizon Wireless and AT&T expand existing networks at a rapid pace.