The Mercian Sphere is the second studio album by the English black metal band Winterfylleth, released on 12 July 2010 through Candlelight Records.

The black metal band Winterfylleth formed in Manchester in 2007 by the drummer Simon Lucas and vocalist and guitarist Chris Naughton.

[1] Between the first and second album, the band replaced its bass guitarist, who attracted attention from antifascists for posts on his Myspace page where he used the phrases "wpww"—short for "White Pride World Wide"—and "14w"—referring to the Fourteen Words slogan of the American neo-Nazi David Lane.

[6] The liner notes say the album is "dedicated to all those who are actively involved with the preservation of our great ancestral heritage, history, folklore and rich national culture".

[7] Comparing The Mercian Sphere to The Ghost of Heritage, the scholar Karl Spracklen says it is "more ambiguous in its lyrics about race and nation, though it is still mainly about Anglo-Saxon men fighting for England".