Check out the
EDAstro map of neutron stars that have been reported to EDSM. You can clearly see the "neutron fields" in question are two huge discs tens of thousands of LY across, spanning almost the entire galaxy. There's probably a billion neutron stars in each field. You've just discovered one small part of one of them.
The ED galaxy is stratified by age: the closer you get to the galactic plane or "equator", the younger the average age of the stars gets. This is intended to mirror what we see in the real-life galaxy, except the real-life galaxy doesn't have that sharp boundary of the neutron fields, whcih is an artifact of the algorithms used to create the galaxy.
Neutron Stars and Black Holes are the result of large stars dying and exploding as supernovae, and large stars don't last very long on galactic timescales. At neutron-field height, most of the large stars have already exploded, and most of the medium ones have either exploded too, or become Red Giants / White Dwarfs. So it is entirely realistic for the regions far above and below the galactic plane to be much richer in neutron stars, black holes, Red Giants and White Dwarfs.