  A polyhedral graph is a $3$-connected planar graph. We find the least
possible order $p(k,a)$ of a polyhedral graph containing a $k$-independent set
of size $a$ for all positive integers $k$ and $a$. In the case $k = 1$ and $a$
even, we prove that the extremal graphs are exactly the vertex-face (radial)
graphs of maximal planar graphs.
