Totally? Where?
Chevrolet has been a GM brand since before 1920.
The first Corvettes were made in 1953.
From Wikipedia:
**Originally built in Flint, Michigan and St. Louis, Missouri, it is currently built at a General Motors assembly plant in Bowling Green, Kentucky.
While sold under the Chevrolet marque in the United States and other locations in the world, it is sold under its own Corvette marque in Europe and Japan.**
I doubt that any car sold in the U.S. is “totally” from the U.S., given the number of parts suppliers in Canada, Mexico, and the Pacific rim, but Corvette has a really good claim based on its Bowling Green, KY manufacturing plant.
I made the closeouts that go around the headlamps on the C6 'Vette. I got to go into the assembly plant right after the model changeover from C5 to C6.
Since they were still working the bugs out, the line would be up for about a minute and then down for a half-hour or so. When the line was down, everyone just sat down and waited.
I saw someone taking a nap inside a Vette while the line was down.
It’s pretty neat to see an automotive assembly line. Except when you are the reason the line is not running.
And yes, the assembly plant is in BG, Kentucky. They give tours there.
Our part went on a headlamp supplied by Carplastics S.A. (in Monterrey Mexico) which is owned by Visteon. Visteon used to be owned by Ford. And of course, Corvette is a GM brand.
Visteon/Carplastics also supplies the headlamp for the Hummer.
I realize the car has a long history here, but it’s usually had “cousins”. It seems lonely now.
Stop the presses! Looking for old Z28 info I just learned GM has released the well endowed 2010 Camaro GT. Not bad.
I don’t think you can find any record of an original Corvette model being built by any manufacturer other than Chevy and/or GM.
As for “totality”, the common wisdom is that the Ford F-150 has the highest domestic content of any mass produced vehicle built in the USA and that figure is at about 80%. The Corvette may not be included in those figures because it could fall under the threshold of being mass produced. It may be more, it may be less.
The Corvette is “American” and I don’t say that as a Corvette fan.
Does that mean it comes with a car bra? 
No, but it comes with a SS rather than a GT. It also comes with a jock strap. 
Okay, okay. Girls can drive it too.
I meant “built” here, and not in Canada or Australia or something.
I’m not a Corvette fan, but I think it’s a pretty cool car.
I think the last total American car was an Oldsmobile or Buick model back in the 80s