  We present the first lattice calculation of the nucleon isovector unpolarized
generalized parton distribution (GPD) at the physical pion mass using a lattice
ensemble with 2+1+1 flavors of highly improved staggered quarks (HISQ)
generated by MILC Collaboration, with lattice spacing $a\approx 0.09$~fm and
volume $64^3\times 96$. We use momentum-smeared sources to improve the signal
at nucleon boost momentum $P_z \approx 2.2$ GeV, and report results at nonzero
momentum transfers in $[0.2,1.0]\text{ GeV}^2$. Nonperturbative renormalization
in RI/MOM scheme is used to obtain the quasi-distribution before matching to
the lightcone GPDs. The three-dimensional distributions $H(x,Q^2)$ and
$E(x,Q^2)$ at $\xi=0$ are presented, along with the three-dimensional nucleon
tomography and impact-parameter--dependent distribution for selected Bjorken
$x$ at $\mu=3$ GeV in $\overline{\text{MS}}$ scheme.
