  We study a large class of supersymmetric solutions in four-dimensional $N=5$
gauged supergravity with $SO(5)$ gauge group. There is only one $N=5$
supersymmetric $AdS_4$ vacuum preserving the full $SO(5)$ symmetry dual to an
$N=5$ SCFT in three dimensions. We give a number of domain walls interpolating
between this $AdS_4$ fixed point and singular geometries in the IR with $SO(4)$
and $SO(3)$ symmetries. These solutions describe RG flows from the $N=5$ SCFT
to non-conformal field theories driven by mass deformations. The $SO(4)$
solutions are precisely in agreement with the previously known mass
deformations within the dual $N=5$ SCFT. We also find supersymmetric Janus
solutions describing two-dimensional conformal defects in the $N=5$ SCFT with
$N=(4,1)$ and $N=(1,1)$ supersymmetries on the defects. Finally, we study
supersymmetric solutions of the form $AdS_2\times \Sigma^2$, with
$\Sigma^2=S^2,H^2$ being a Riemann surface, corresponding to near horizon
geometries of $AdS_4$ black holes. We consider both magnetic and dyonic
solutions and find that there exists a class of magnetic $AdS_2\times H^2$
solutions with $SO(2)$ symmetry. It is rather remarkable that a complete
analytic solution interpolating between $AdS_4$ and $AdS_2\times H^2$ with a
running scalar can be obtained. The solution corresponds to a twisted
compactification of $N=5$ SCFT to superconformal quantum mechanics. We also
show that no purely magnetic or dyonic black holes with $AdS_2\times \Sigma^2$
horizon from $SO(2)\times SO(2)$ twist exist in $N=5$, $SO(5)$ gauged
supergravity.
