  We present the transport and capacitance measurements of 10nm wide GaAs
quantum wells with hole densities around the critical point of the 2D
metal-insulator transition (critical density $p_c$ down to
0.8$\times10^{10}$/cm$^2$, $r_s\sim$36). For metallic hole density $p_c < p
<p_c +0.15\times10^{10}$/cm$^2$, a reentrant insulating phase (RIP) is observed
between the $\nu$=1 quantum Hall state and the zero field metallic state and is
attributed to the formation of pinned Wigner crystal. Through studying the
evolution of the RIP versus 2D hole density by transport and capacitance
experiments, we show that the RIP is incompressible and continuously connected
to the zero field insulator, suggesting a similar origin for these two phases.
