The NFA provides a lot of information with regards to CTAs and more importantly allows any prospective investor to do a naive background check on any manager that they intend to invest with. Part of the database shows the location of registered CTAs.
It may not come as a complete surprise to visitors of this website, but an overwhelming majority of the registered CTAs are based in the US. A handful can be found in Europe, with the UK in the top.
In terms of location, New York, Illinois and California are the the most popular location for running a CTA business. A number of states seems to rather underserviced by managers with a few of them only recording three managers. Network effects are presumably powerful as emerging managers probably learned the trade from an existing CTA. In larger hubs or states, it is most likely also easier to find capital.