Guys The Big River.....Rio Grande
Not if you speak with a Northern Minnesota dialect as I do. Rio Grande was what Dad said when he meant the equivalent of being "Up *$#t Creek." Where I come from, Spanish is considered a foreign language, so we pretty much ignored it.
That hobbles my interpretive skills when I travel to places outside of my provincial surroundings, where Northern MN dialect is far more of a foreign language than Spanish.
Given my very local upbringing, Big River for me is the Mississippi. The Big Muddy is the Missouri. Sorry for any confusion.