Wilderlands of the Magic Realm (1979)

From the web:

The third supplement in Judges Guild's Wilderness series. It details the villages, castles, citadels, lairs, islands, ruins, and terrain in a section of the Wilderlands of High Fantasy campaign setting. It consists of two 16-page booklets (one 48-page book in later printings) and two double-sided 17" x 22" maps (2 for the judge, 2 for the players):

Campaign Map #11: Ghinor
Campaign Map #12: Isle of the Blest
Campaign Map #13: Ebony Coast
Campaign Map #14: Ament Tundra

There are over 300 islands detailed on the maps and described in the accompanying book, which also covers the area's resources, wilderness monster lairs, villages and castles, technological levels, civilizations and more. The third of the wilderness series, the Magic Realm covers the settlements of Oricha and Chim and extends the areas already covered to the south, far into the vast reaches of the Sea of Five Winds. The four maps (2 Judge, 2 Player) include with the 2nd and 3rd printings are: Campaign Map #11: Ghinor / Campaign Map #14: Ament Tundra and Campaign Map #12: Isles of the Blest / Campaign Map #13: Ebony Coast.