A few to add:
St. Lawrence - Montréal, Kingston!
Tiber - Rome
Vistula - Warsaw
Mississippi (another answer) - Memphis
Seine (another answer) - Dijon?
Plata: Buenos Airies
Fraser: Vancouver
I know nothing else. Perhaps not even that.
Spree - Berlin
Po - Venice
IJ - Amsterdam
Yangtze Kiang - Shanghai?
Dniepr - Kiev?
Tigris - Baghdad?
Congo - Kinshasa?
Nope.
If I don’t respond to you specifically, it means you’re right 
Ones remaining:
Manzanares
Guadalquivir
Nervion
Po
Scheldt
To which I’ll add:
Bow
Charles
Red: Hanoi
Po - Florence, Italy
Charles - Boston, MA
Thames - what, nobody has mentioned the bustling metropolis of New London, CT? Why, those Brits can’t even pronounce it right! 
Although I must add: New London is not the major city on the Thames - Groton is. (Not that either one is really “major” in the grand scheme of things.) But Groton has been mysteriously maligned for years. Even the DoD identifies its base as Naval Submarine Base New London - and it’s NOT in New London at all.
Now, back to your regular programming.
Nope…
Thank you!
We’re still missing the Bow and a city on the Congo.
Congo- Brazzaville
Bow- (WAG) Sydney??
Yup!
Nope. C’mon, I know there are dopers who even LIVE in this city…
Bow - Calgary
Us Canadian Dopers have to stick together, matt_mcl .
Sydney’s river is the Parramatta
Why did everyone at first say New Orleans for the Mississippi? And thanks for the later nod to my hometown, Memphis, but neither one of those is the largest city on the Muddy, which is St. Louis. Unless the Twin Cities (Mineapolis/St. Paul, where the curious among us, like myself, can go to see Lock & Dam #1) count as one, in which case… St. Louis is probably still bigger than both of them, actually.
That’s my two cents. Oh yeah, and how about the Chattahoochee? St. Johns? Willamette? Raccoon? (These are all American rivers.)
Beuhler?
Willamette - Portland, OR
Chattahoochee - Atlanta?
Chattahoochee sounds more like Orlando or Tallahasee.
How about 4 on the Rio Grande?
Or one on the Grand River?
or the San Joaquin?
Rio Grande - El Paso
Albuquerque
Alright, I cheated a little by asking a friend who knew the area a little, so sue me.
You forgot the easiest answer of all. What city is located on the Detroit River?
Off the top of my head:
Windsor, Ontario
Amherst, Ontario
Grosse Pte., MI
Grosse Pte. Park, MI
Delray, MI
Dearborn, MI
Allen Park, MI ?
Lincoln Park, MI
Wyandotte, MI
Grosse Isle, MI
Flat Rock, MI ?