^^^It should be noted that the same report actually places DT Jax at 38,000 employees, which falls in line with what we have been saying here, but doesn't seem to jive with lots of the other small downtowns in the country that are estimated as having larger employment numbers, but are clearly smaller. The 56,000 number comes from the secondary employment center named "JAcksonville Medical Center", which I think we can infer means the Southbank, and the Northbank is close enough where its employment numbers would be counted...as well as Riverside.
It should also be noted that usually state capitals (especially in the small-mid size) are way overcounted for various reasons. Same goes for towns with universities right in their center (Austin comes to mind).
It should also be noted that Boston isn't even counted because statistics aren't officially kept in MA.
It should finally be noted that there are secondary employment centers such as Koreatown/Wilshire in LA, Brooklyn (admittedly over-counted due to the nature of the functions that downtown serves), Las Vegas Strip, Irvine CA, and others that are massively large and in the top 20 of all employment centers in the country.
Also, want to point out that DC is the "4th largest DT" in America with 468K workers, AND 50.5% of residents within 1 mile of the outer edge of downtown also work downtown (very high %), AND a whopping 173K residents lives within its CBD's loose borders (higher than notably dense cities like SF despite water taking up half of the area, Lower Manhattan despite water taking up half its area, DT Chicago despite water taking up half its area, and Center City Philadelphia), . This is all patently misleading because when you look at employment density it falls wayyy short (97 employees per acre, behind all of the majors, several secondary centers, and places like Cincinnati and St. Paul MN). Basically DC is a mega sprawling downtown no thanks to its height limits.
We can deduct that with 468K employees at an average of 97 employees/acre, that its CBD sprawls 7.5 square miles. Add 1 mile out from its borders and you get 22.45 sq miles. 173K people live within these 22.45 sq miles, or 7,704ppsm, which is less than the DC average of 10,300 ppsm.
Contrast Jacksonville's 56,000 employees at avg density of 44 jobs/acre (I used the higher Jax Medical Center figures as opposed to DT Jax figures), and you're at 2 sq mi. Add 1 mile to each side and you're at 16 sq mi. 25,000 people live within this area (I used the higher "downtown Jax" figures rather than the "Jax Medical Center" figures), which of course includes a good bit of water. 1,563 ppsm around downtown. Not a good sign - need to build that up to a "uniform" 3-4,000ppsm across all 16 sq miles.
BTW, none of the FL downtowns have a "dense" downtown when it comes to employment. The most dense is Tampa at 87 jobs/acre and at only 1.5 sq mi is actually one of the smaller downtowns. It sustains a moderate employment density over a small area. Miami has 188,000 DT employees, but spread all over between DT, Brickell, and other submarkets that are half-heartedly connected, such that its employment density is only 52 jobs/acre and its downtown is a whopping 5.65 sq mi, one of the largest in the country. Yet it packs residential punch with 141,000 residents within 1 mile of this large downtown area (and considering water takes up lots of this are). Its downtown still feels quiet and dead to me because the residents are often part-time, the buildings are gated, and there isn't much of a concentrated employment base as compared to other downtowns.
Jax would do wise to not just focus on residential and tourism, but also office employment growth downtown. Relatively speaking compared to other parts of town, Lower Manhattan, SF's Financial District, Chicago's Loop, and Boston's financial district all shut down. But they are still ZOOMING at least 15 hours a day. 5:30 AM til about 8:30 PM where I live, all driven by office (4th most dense downtown behind the 2 New Yorks and Chicago, and I don't even believe LA's #s for a second knowing that market a fair bit).