For all Mecklenburgophiles here who want to appear extra Mecklenburg-savvy:
The original, correct (North) German pronunciation of the name is [ˈmeːklənbʊrk] with the first vowel long, as if written Meecklenburg.
Apparantly doubling the following consonant was a way to indicate a long vowel in medieval Low German. (Mecklenburg means "Big Town/Castle" and is cognate with Miklagard, the Vikings' name for Constantinople.)
The Slavic Wendish name of the original castle Mecklenburg (between Schwerin and the Baltic) was Wiligrad (same meaning), a name that later was recycled for the castle Duke Johann Albrecht built by the Lake of Schwerin in the 1890s.
Schloss Wiligrad: