  We compiled a catalog of Faraday rotation measures (RMs) for 4553
extragalactic radio point sources ublished in literature. These RMs were
derived from multi-frequency polarization observations. The RM data are
compared to those in the NRAO VLA Sky Survey (NVSS) RM catalog. We reveal a
systematic uncertainty of about $10.0 \pm 1.5$\,rad~m$^{-2}$ in the NVSS RM
catalog. The Galactic foreground RM is calculated through a weighted averaging
method by using the compiled RM catalog together with the NVSS RM catalog, with
careful consideration of uncertainties in the RM data. The data from the
catalog and the interface for the Galactic foreground RM calculations are
publicly available on the webpage: http://zmtt.bao.ac.cn/RM/.
