"It is a long-term, continuing struggle for so many people in the region," McGraw and Hill said in a joint statement. "This year we are focusing attention on the needs of Mississippi."

Last year, Neighbor's Keeper held a benefit show in New Orleans that marked the return of the concert industry to the region. With that and other contributions, the organization has donated $1 million to the Community Initiative Foundation of Baton Rouge, LA, which runs art therapy programs for children and young adults at the Renaissance Camp, the largest trailer city in Baton Rouge.

McGraw and Hill are in the midst of their 44-date, North American Soul2Soul Tour 2007, which launched in early June with record-breaking performances in Omaha, NE, and St. Paul, MN, according to a press release. The outing continues tonight (7/25) in Tampa, FL, and will hit the South and West Coast before wrapping with a two-night stand Aug. 10-11 in Anaheim, CA. Dates are listed below.

Last month, the singers completed a nine-show run of Canada, marking their first string of dates throughout the country. They'll return to the Great White North Sept. 1 for their only outdoor gig of the year at Country Rocks the Hill in Moncton, New Brunswick.

Last year's Soul2Soul outing was logged as the highest-grossing country music tour in history and the 12th highest-grossing tour of all time, according to concert-industry publication Pollstar.