We measure the circular velocity curve v _ { c } ( R ) of the Milky Way with the highest precision to date across Galactocentric distances of 5 \leq R \leq 25 kpc . Our analysis draws on the 6 -dimensional phase-space coordinates of \gtrsim 23 , 000 luminous red-giant stars , for which we previously determined precise parallaxes using a data-driven model that combines spectral data from APOGEE with photometric information from WISE , 2MASS , and Gaia . We derive the circular velocity curve with the Jeans equation assuming an axisymmetric gravitational potential . At the location of the Sun we determine the circular velocity with its formal uncertainty to be v _ { c } ( R _ { \odot } ) = ( 229.0 \pm 0.2 ) km s ^ { -1 } with systematic uncertainties at the \sim 2 - 5 \% level . We find that the velocity curve is gently but significantly declining at ( -1.7 \pm 0.1 ) km s ^ { -1 } kpc ^ { -1 } , with a systematic uncertainty of 0.46 km s ^ { -1 } kpc ^ { -1 } , beyond the inner 5 kpc . We exclude the inner 5 kpc from our analysis due to the presence of the Galactic bar , which strongly influences the kinematic structure and requires modeling in a non-axisymmetric potential . Combining our results with external measurements of the mass distribution for the baryonic components of the Milky Way from other studies , we estimate the Galaxy ’ s dark halo mass within the virial radius to be M _ { vir } = ( 7.25 \pm 0.26 ) \cdot 10 ^ { 11 } M _ { \odot } and a local dark matter density of \rho _ { dm } ( R _ { \odot } ) = 0.30 \pm 0.03 GeV cm ^ { -3 } .