  We examine the three-dimensional structure and dust extinction properties in
a ~ 200 pc $\times$ 100 pc region in the southwest bar of the Small Magellanic
Cloud (SMC). We model a deep Hubble Space Telescope optical color-magnitude
diagram (CMD) of red clump and red giant branch stars to infer the dust
extinction and galactic structure. We model the distance distribution of the
stellar component with a Gaussian and find a centroid distance of 65.2 kpc
(distance modulus $\mu$ = 19.07 mag) with a FWHM $\approx$ 11.3 kpc. This large
extent along the line of sight reproduces results from previous studies using
variable stars and red clump stars. Additionally, we find an offset between the
stellar and dust distributions, with the dust on the near side relative to the
stars by 3.22 $^{+1.69}_{-1.44}$ kpc, resulting in a 73% reddened fraction of
stars. Modeling the dust layer with a log-normal $A_V$ distribution indicates a
mean extinction $\langle A_V \rangle$ = 0.41 $\pm$ 0.09 mag. We also calculate
$A_V/N_H$ = 3.2 - 4.2 $\times10^{-23}$ mag cm$^2$ H$^{-1}$ which is
significantly lower than the Milky Way value but is comparable to previous SMC
dust-to-gas ratio measurements. Our results yield the first joint dust
extinction and 3D geometry properties in a key region in the SMC. This study
demonstrates that CMD modeling can be a powerful tool to simultaneously
constrain dust extinction and geometry properties in nearby galaxies.
