My home town.
MO recognizes NE for CCW reciprocity.
But..................Be sure to read up on all the CCW rules for Missouri, then check to see if St. Louis has any special CCW rules, ordinances, or laws of its own. St. Louis, like Omaha, has always considered itself to be a separate entity unto itself.
For example, in the 1870s or so, it seceded from St. Louis County. The City of St. Louis is not in any Missouri county. Blank space on my birth certificate. Always have had official forms returned to me on that one. City police do not report to the mayor's office; they report to the governor of the State of Missouri. Goes back to the Civil War. Many peculiarities there.
As a further example, I seem to recall that CCW is not allowed on public transportation in St. Louis. But--YOU check everything out personaly, yourself, before carrying in town. Plenty of MO/StL CCW info on the web.
And you will feel much better with some concealed Social Security as you go around the inner parts of the city or North St. Louis County. It's a jungle out there. Lotsa druggies, muggings, murders, etc. At least, it was last July when we visited.
Many public places are posted. The St. Louis Arch (actually, federal facility), for example. I had to stay outside and wait for the rest of the group to finish their tour. Our hotel on Grand Avenue was posted. Watch for the signs. But....be sure to do your web research and read the fine print in the laws.
Plus.....St. Louis is totally surrounded by over 100+ different little municipalities, cities, whatever. A good many of them have their own ordinances regarding handguns. Including some where written permission from property owners is required before entering with a handgun.
Good Luck.