  We present a stellar dynamical mass measurement of the supermassive black
hole in the elliptical (E1) galaxy NGC 3258. Our findings are based on integral
field unit spectroscopy from the Multi Unit Spectroscopic Explorer (MUSE)
observations in narrow-field mode with adaptive optics and the MUSE wide-field
mode, from which we extract kinematic information by fitting the Ca II and Mg
$b$ triplets, respectively. Using axisymmetric, three-integral Schwarzschild
orbit library models, we fit the observed line-of-sight velocity distributions
to infer the supermassive black hole mass, the $H$-band mass-to-light ratio,
the asymptotic circular velocity, and the dark matter halo scale radius of the
galaxy. We report a black hole mass of $(2.2 \pm 0.2)\times10^9 \ \rm
M_{\scriptscriptstyle\odot}$ at an assumed distance of $31.9 \ \rm Mpc$. This
value is in close agreement with a previous measurement from Atacama Large
Millimeter/submillimeter Array CO observations. The consistency between these
two measurements provides strong support for both the gas dynamical and stellar
dynamical methods.
