This is true. In central Illinois, 2.5 hours from STL, I constantly have to explain this WashU is neither in Seattle nor (sometimes) American's Washington College of Law.
That's really weird. WashU is a well known school anywhere I've ever lived.
Wash U is kind of a weird animal in the St. Louis area.
I grew up within 40 miles of the school, and until I met a Wash U transfer in my undergrad, had never known someone who attended the school.
It's hard to explain to people, especially from the Northeast, but in this area no one even thinks about going to prestigious/ivy league schools. While Wash U is a fantastic school (undergrad is top 15, med school is top 5), most of the students are from other parts of the country. Sure, some of the smartest kids in St. Louis go to Wash U, but at the high school I graduated from (small) I was the only one who even considered attending. Despite it being a great school, it's definitely not integrated into the community, or at least people's minds as much as other local schools like SLU or Mizzou. Locals know it's considered a "really good" school, but they probably know nothing about it other than that.