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Using high-resolution ultraviolet spectra obtained with the HST/SpaceTelescope Imaging Spectrograph (STIS) and the Far Ultraviolet SpectroscopicExplorer, we study the metallicity, kinematics, and distance of the gaseous"Outer Arm" (OA) and the high-velocity clouds (HVCs) in the outer Galaxy. Wedetect the OA in a variety of absorption lines toward two QSOs, H1821+643 andHS0624+6907. We search for OA absorption toward eight Galactic stars and detectit in one case, which constrains the OA Galactocentric radius to 9<R_{G}<18kpc. We also detect HVC Complex G, which is projected near the OA at a similarvelocity, in absorption toward two stars; Complex G is therefore in the sameregion at R_{G} = 8 - 10 kpc. HVC Complex C is known to be at a similarGalactocentric radius. Toward H1821+643, the low-ionization absorption linesare composed of multiple narrow components, indicating the presence of severalcold clouds and rapid cooling and fragmentation. Some of the highly ionized gasis also surprisingly cool. Accounting for ionization corrections, we find thatthe OA metallicity is Z=0.2-0.5 Z_{solar}, but nitrogen is underabundant andsome species are possibly mildly depleted by dust. The similarity of the OAmetallicity, Galactocentric location, and kinematics to those of the adjacentouter-Galaxy HVCs, including high velocities that are not consistent withGalactic rotation, suggests that the OA and outer-Galaxy HVCs could have acommon origin.

The 21cm "Outer Arm" and the Outer-Galaxy High-Velocity Clouds: Connected by Kinematics, Metallicity, and Distance