INTRODUCTION 
This gazetteer, the third edition, contains approximately 6,000 names for undersea features of the world. 
Of these names, 3,600 are jointly approved by the Board on Geographic Names (BGN) and the Secretary of 
the Interior. The remaining 2,400 names are unapproved variants. The Board and the Secretary are 
responsible for standardizing geographic feature names for Federal Government use. Research for this 
publication was completed in May 1981. 
‘Undersea features” are parts of the ocean floor or seabed that have measurable relief or can be 
delimited by relief. Geographic names are not approved for geological or geophysical features that have 
no surface expression, e.g., magnetic features. 
This gazetteer incorporates new names, changes to some older names, and other modifications 
approved since the second edition (1971). The undersea feature names in this publication supersede those 
in all previous BGN Gazetteers or in other Defense Mapping Agency publications. 
Format of the gazetteer 
The first section of the gazetteer is an alphabetized, cross-referenced list of names used for undersea 
features. The second section lists the same names within blocks bounded by parallels and meridians at 30° 
intervals as shown on the map which accompanies that section. 
The first column of the gazetteer contains both approved and unapproved names. Those which are 
unapproved are cross referenced to the approved form by use of the word “‘see.”’ 
The second column contains designations that identify the kind of topographic feature to which the 
name applies. The designator is usually the same as the generic term (see ‘‘Naming of features’’) in the 
approved name. However, it will differ when a generic that is not properly descriptive under BGN defini- 
tions is retained as part of the name because of established usage. 
The third and fourth columns contain geographic coordinates, with the longitude based on 
Greenwich. Coordinates are taken at the center of the feature and serve only for identification. 
