The name of Jacksonville itself is a bit of a contrivance. The people who actually lived here petitioned Spain to name the place St. Nicholas, a notch up from Cow Ford, as the itinerant Brits called it. Spain demurred, however, for reasons lost to history, or at least to me, so a guy from out of town suggested the place be named for Andy Jackson, a splendid fellow, and three newcomers from Georgia went along. Years later there was an organized move to change the name of Jacksonville. When new owners took over the afternoon newspaper in 1922 they changed the paper's name from the Metropolis to the Journal and mounted a campaign to change the name of Jacksonville to Jackson, as if that would be an improvement.
Buildings change names more often than rivers.
The Heard building became the Florida Title building years ago, before becoming a parking lot. The American Heritage building was the Lynch building. The Elks Club was in the same place for almost a century before it became whatever it is becoming now. St. Johns River Park and Marina, known to all as Friendship Park, was named for somebody else before that. Pablo Beach became Jacksonville Beach.