  The nucleation field for surface superconductivity, $H_{c3}$, depends on the
geometrical shape of the mesoscopic superconducting sample and is substantially
enhanced with decreasing sample size. As an example we studied circular,
square, triangular and wedge shaped disks. For the wedge the nucleation field
diverges as $H_{c3}/H_{c2}=\sqrt{3}/\alpha$ with decreasing angle ($\alpha$) of
the wedge, where $H_{c2}$ is the bulk upper critical field.
