Aug 17 (Reuters) - BB&T Corp said it would buy National Penn Bancshares Inc in a cash and stock deal for about $1.8 billion to expand in the U.S. Mid-Atlantic region.

The deal consideration would consist of 70 percent BB&T shares and 30 percent in cash. National Penn shareholders can opt to receive 0.3206 of a BB&T share or $13 in cash for each National Penn share.

(Reporting by Rama Venkat Raman in Bengaluru; Editing by Lisa Shumaker)