Here in the US, we’d say “gone off to college” or “going to [university name]”, where the university’s name is almost always abbreviated (e.g. UW for University of Washington, Caltech for California Institute of Technology, etc.).
The only times I’ve heard “at university” is from british or australian comedians. “He’s away at university” without a “the” in it sounds weird to me. Ironically, I’ll bet neither of us would have our accustomed usage marked wrong by a proofreader.
The mouths of the Mississippi, the Ohio, and the Colorado are in Louisiana, Illinois/Kentucky/Missouri, and Mexico (unless you mean the Colorado river in Texas). You did get Arkansas right.
It does, and that’s not a good example, but that’s one of those things that, in US English anyway, articles and prepositions can change the meaning. “He’s at the college,” means that right now, he is physically at whatever college is understood by the speaker and listener for “him” to have some purpose to be at. He may not be a student-- he may be on the janitorial staff, or the Vice President, or there to buy tickets to the theater department’s production of My Fair Lady. “He’s in college” means he is currently a student, enrolled, probably full-time working toward a degree, in a college. He may not be there now-- he may be hundreds of miles from campus, because it’s summer break, but he’s still “in college.” For some reason, when someone is enrolled in a big university in one of the schools that is not part of the College of Arts and Sciences, but one of the specialty schools, like the school of nursing, or the school of music, most people would probably still say the person in “in college.”
We do the same thing with prepositions in other situations “in the hospital” means something different from “at the hospital.” Something that is very hard to explain to a non-native speaker.
In English worldwide, there’s the same distinction with or without the article for “college”, “school”, “church”, “jail”, and a few others: Including the article just means that you’re physically at the location (janitor, at a PTA meeting, organizing the rummage sale, visiting an inmate, whatever), while leaving it off means that you’re a client, so to speak, of the institution (student, worshiper, prisoner, etc.). Everywhere but the US, “hospital” works the same way; it’s just that one word that the US differs on.
I started a thread long ago about why some groups of mountains are The ____Mountains, while others are The____Range. No real reason, just whatever somebody decided to call them. Most of the mountains in Alaska are in Ranges, while it seems most mountains elsewhere in the states are in Mountains. Even more confusing, there are mountain ranges out there.
For the most part, that’s only true of very large and important lakes. Small lakes most often have the generic at the end—unless they’re putting on airs for some reason or sometimes for no good reason at all.
A Google search shows many instances of it used without the article. In fact, it mainly appears with the article in reference to “the Puget Sound area (or region).”
Most of the time, I just hear The ________. Like, I have only ever heard “The Sierras”, I guess because “Sierra Mountains” would be kind of redundant. Or the Sangre de Cristos I think are rarely referred to as the Sangre de Cristo Mountains. However, by my old hometown, I think they always say “The Blue Mountains”, to avoid confusion with sadness or music.
That can’t be the explanation, because in British English the word ‘River’ goes before the name. So, it’s ‘the River Thames’ etc., not ‘the Thames River’. What’s more, that’s been the standard form in British English since before there was such a thing as American English.
“The Manila Bay” is also common here in our place. It might have something to do with the naming. A familiar first name will require an article. Exception is Lake Michigan.
Rivers are sometimes referred to without “River” in the name;e.g., the Potomac, the Ashley, etc., and it is known that you are referring to that river. Not so with other bodies of water. This doesn’t hold true for rivers that may cause confusion. I’ve never heard the Chicago River referred to as “the Chicago,” but the Illinois river is often called just “the Illinois.”
I was going to point that out also, the “the” in that case really isn’t attached (or whatever the term is) to “puget sound” is attached to “area/region”, that’s the only time I hear “the” in front of “puget sound”.