  Aims. The extraplanar stellar populations of highly-inclined disk galaxies IC
2233, IC 5052, NGC 4631 and NGC 5023 are analyzed with the goal to quantify
their vertical extent and structure.
  Methods. Based on the single-star photometry, we separate different stellar
populations and analyze their spatial distribution. Results. On archival images
obtained with the Hubble Space Telescope ACS/WFC the surroundings of these
galaxies are well resolved into stars with the red giant population (RGB)
identified far above the galaxy mid-planes. We find that there are a profound
change in slope of the number density profile of the evolved RGB stars at
extraplanar height of 4-8 kpc, that possibly reflects a truncation of the thick
disk and reaching the 2-3 times more extended oblate stellar component (``the
halo''). This structure is consistent with our previous studies of both edge-on
and face-on disk galaxies in the Local Universe and allow us to improve the
spatial model of the stellar components of a typical spiral galaxy. In NGC4631,
the revealed asymmetry of its stellar thick disk and halo, is likely caused by
the neighbor dwarf galaxy NGC4627. Based on the tip of the red giant branch
method (TRGB) we estimated a distance of 10.42+/-0.38 Mpc for IC2233,
5.62+/-0.20 Mpc for IC5052, 7.11+/-0.13 Mpc for NGC4631 (6.70+/-0.15 for its
satellite NGC4627) and 6.14+/-0.15 Mpc for NGC5023. We confirm the presence of
slight extraplanar metallicity gradient of evolved stars at NGC5023 and IC5052,
based on the systematic changes of the colour distribution of red giant stars.
