Job mobility is essential for a well-functioning market economy and for individual workers to boost their wages. This paper provides a re-assessment of job mobility in the United States during 2000-2018, based on a novel administrative data source covering almost all workers and job flows. First, aggregate job hire and job separation rates have declined over time, especially in the 2000s. This is mainly driven by flows into and out of nonemployment, while job-to-job hires during 2016-2018 had recovered to their peak levels prior to the global financial crisis. Examination of job mobility across different individual and firm-level characteristics shows comparatively higher job-to-job flows for youth, the less educated, non-whites and individuals working in young firms. In addition, observed job movers in these groups experience the largest earnings gain on average from job-to-job changes. Second, a spatial look at job mobility shows net job-to-job flows towards Western and Southern States. The aggregate rate of interstate job-to-job hires has been stable since 2000 and the observed job-to-job movers on average get a substantial boost to earnings by moving farther away and switching industries. Third, the paper briefly considers the influence of demographic changes on job mobility, one important driver identified in previous work. While ageing may explain around half of the downward trend in job hire and separation rates, other factors matter too.