According to MusicWeek, the record shifted 481,000 copies in its first seven days, the fourth highest weekly sale of any album in the past year.
The Nashville trio, made up of Charles Kelley, Hillary Scott and Dave Haywood, reached number four with their self-titled debut in 2008.
Elsewhere, The 'Hope For Haiti Now' charity album drops one place to two and Lady GaGa's The Fame holds steady at three.
Barry Manilow's Greatest Love Songs Of All Time enters at number five, while Corinne Bailey Rae's second album The Sea debuts at seven.
Bailey Rae sold 53,000 copies of The Sea, beating the 40,000 sales and number 17 start of her self-titled debut in 2006.