In this article we are interested in the nonlocal regional Schrödinger equation with critical exponent (Formula presented). where ϵ is a small positive parameter, α∈(0,1), q∈(1,2∗α−1), 2∗α=2n/(n−2α) is the critical Sobolev exponent, λ>0 is a parameter and (−Δ)αρ is a variational version of the regional Laplacian, whose range of scope is a ball with radius ρ(x)>0. We study the existence of a ground state and we analyze the behavior of semi-classical solutions as ε→0.