A grand rotation curve of the Milky Way Galaxy was constructed, which covers a wide range of radius from the Galactic Center to $ \sim$ 1 Mpc, and was deconvolved into bulge, disk, and halo components by least-squares fittings. We determined the masses and scale radii of the bulge and disk to be $ {M_{\rm b}}$$ =$ (1.652 $ \pm$ 0.083) $ \times$ 10$ ^{10}{\ M_\odot}$ , $ {a_{\rm b}}$$ =$ 0.522 $ \pm$ 0.037 kpc, $ {M_{\rm d}}$$ =$ (3.41 $ \pm$ 0.41) $ \times$ 10$ ^{10}{\ M_\odot}$ , and $ {a_{\rm d}}$$ =$ 3.19 $ \pm$ 0.35 kpc. The dark halo was fitted by the Navaro–Frenk–White (NFW) density profile, $ \rho$$ =$$ \rho_0/$ [($ R/h$ )(1 $ +$$ R/h$ )$ ^2$ ], and the fit yielded $ h$$ =$ 12.5 $ \pm$ 0.9 kpc and $ \rho_0$$ =$ (1.06 $ \pm$ 0.14) $ \times$ 10$ ^{-2}\ M_{\odot}$ pc$ ^{-3}$ . The local dark-matter density near the Sun at $ R_0$$ =$ 8 kpc was estimated to be $ \rho_0^\odot$$ =$ (6.12 $ \pm$ 0.80) $ \times$ 10$ ^{-3}\ M_{\odot}$ pc$ ^{-3}$$ =$ 0.235 $ \pm$ 0.030 GeV cm$ ^{-3}$ . The total mass inside the gravitational boundary of the Galaxy at $ R$$ \sim$ 385 kpc, a half distance to M 31, was estimated to be $ {M_{\rm b+d+h}}$$ =$ (7.03 $ \pm$ 1.01) $ \times$ 10$ ^{11}\ M_{\odot}$ . This leads to a stellar baryon fraction of $ {M_{\rm b+d}}/{M_{\rm b+d+h}}$$ =$ 0.072 $ \pm$ 0.018. Considering the expected baryon fraction in the Local Group, we suggest that baryons in the form of hot gas are filling the dark halo with a temperature of $ \sim$ 10$ ^{6}$ K and an emission measure of $ \sim$ 10$ ^{-5}$ pc cm$ ^{2}$ . Such hot halo gas may share a small fraction of the observed X-ray background emission.