Wow, what's up with the Riverside punches today? Is this all about the King Street residential/commercial conflicts?
Anyway, the census tracts combine Riverside/Avondale with Brooklyn. That total number is 15,228 residents at a population density of 4,465.69 per square mile.
For comparison's sake, Springfield's number is 3,726 residents at 3,922.11 people per square mile.
Durkeeville/Moncrief's number is 20,990 residents at 4,456.48 people per square mile. My guess is the Durkeeville area has higher density over a wider expanse of land but one of it's largest census tract is mostly industrial.
San Marco's tracts are combined with the Southbank. That number comes out to 6,812 residents at 3,423 people per square mile.