Q: Some geographical nouns seem to require “the” while others don’t. She vacations on Cape Cod, but climbs the Alps. We sail up the Nile, but swim in Lake George. Is there any logic here?
A: The definite article “the” was once seen more often in place names than it is today. But this convention is still very much with us, and logical or not, there are a few broad rules of thumb.
First of all, we use the article with the names of oceans, gulfs, and rivers: “the Pacific,” “the Nile,” “the Mississippi,” “the Ganges,” “the Caribbean,” etc.
We also use “the” with names for deserts: “the Sahara,” “the Mojave,” “the Kalahari,” and so on.
And we use “the” with the names of mountain ranges and groups of islands that are expressed as plurals.
This accounts for usages like “the Adirondacks,” “the Himalayas” (mountain ranges); “the Bahamas,” “the Hebrides” (island groups), and others.
However, “the” is generally not used with singular names for individual mountains and islands (“Mount Rainier,” “Oahu”), though there are exceptions.
The definite article is used, for example, with mountains like Switzerland’s “the Matterhorn” and “the Jungfrau,” names that the Oxford English Dictionary says are “felt to be descriptive.”
We use “the” with both singular and plural names for regions, as in “the South,” “the Highlands,” and “the Lake District.”
We also use “the” with a singular geographic name that begins with an ordinary noun plus “of,” as in “isle of” and “cape of.”
This accounts for usages like “the Isle of Wight,” “the Isle of Man,” “the Cape of Good Hope,” “the Rock of Gibraltar,” and “the Strait of Hormuz.”
As the OED notes, “the” was formerly “used more widely” in geographic names, especially the names of countries.
The dictionary mentions old usages like “the Argentine,” “the Congo,” “the Lebanon,” “the Sudan,” and “the Yemen” (we might add “the Ukraine”). We no longer use “the” with these names, and of course “the Argentine” is now simply “Argentina.”
The names of some countries have included “the” because they were originally named for a river, a region, a desert, or a mountain range. One such country that still retains its article, “the Gambia,” was named for the Gambia River.
In addition, “the” is used with countries whose names are plurals, or whose names consist of a common noun that’s modified.
This accounts for “the Netherlands,” “the Seychelles,” “the Dominican Republic,” “the United States,” “the United Kingdom,” and others.
We don’t generally use “the” with names of lakes. A special case is “the Great Salt Lake,” which is exceptional because it’s a descriptive noun phrase consisting of common words.
We haven’t covered all the bases here but we’ve given you a broad outline.
By the way, we ran a blog post a couple of years ago on the use of prepositions with geographical nouns. This will explain why we say “on Cape Cod” but “in the Rockies.”