We derive an accurate mass distribution of the galaxy cluster MACS J1206.2-0847 (z = 0.439) from a combined weak-lensing distortion, magnification, and strong-lensing analysis of wide-field Subaru BVR_c I_cz' imaging and our recent 16-band Hubble Space Telescope observations taken as part of the Cluster Lensing And Supernova survey with Hubble program. We find good agreement in the regions of overlap between several weak- and strong-lensing mass reconstructions using a wide variety of modeling methods, ensuring consistency. The Subaru data reveal the presence of a surrounding large-scale structure with the major axis running approximately northwest-southeast (NW-SE), aligned with the cluster and its brightest galaxy shapes, showing elongation with a ~2:1 axis ratio in the plane of the sky. Our full-lensing mass profile exhibits a shallow profile slope dln Σ/dln R ~ –1 at cluster outskirts (R ≳ 1 Mpc h ^(–1)), whereas the mass distribution excluding the NW-SE excess regions steepens farther out, well described by the Navarro-Frenk-White form. Assuming a spherical halo, we obtain a virial mass M_(vir) = (1.1 ± 0.2 ± 0.1) × 10^(15) M_☉ h^(–1) and a halo concentration c_(vir) = 6.9 ± 1.0 ± 1.2 (c_(vir) ~ 5.7 when the central 50 kpc h^(–1) is excluded), which falls in the range 4 ≾ (c)≾ 7 of average c(M, z) predictions for relaxed clusters from recent Λ cold dark matter simulations. Our full-lensing results are found to be in agreement with X-ray mass measurements where the data overlap, and when combined with Chandra gas mass measurements, they yield a cumulative gas mass fraction of 13.7^(+4.5)_(–3.0%) at 0.7 Mpc h^(–1)(≈1.7 r_(2500)), a typical value observed for high-mass clusters.