Wikipedia
Guslitsa, Guslica, or Guslicy is a region situated in the eastern part of Moscow Oblast. Guslitsa is famous for it was almost entirely inhabited by the Old Believers, mainly popovtsy ( Belokrinitskaya Hierarchy, now — Russian Orthodox Old-Rite Church). Name Guslitsa occurs from the Guslitsa River.
Guslitsa is also well known for its cultural heritage and its home-crafts, mainly hand-written singing books and copper mouldings. Guslitsa has its center in the Rudnya and Ilyinsky Pogost villages.
Nowadays Guslitsa lies almost entirely within Orekhovo-Zuyevsky District of Moscow Oblast.
The regions neighboring Guslitsa (currently also unofficial) were also mainly inhabited by the old believers and were influenced by the Guslitsa culture a lot. Among them are: Ramenye, Zakhod, Zaponorye, Patriarshina, Vokhna.