  Context. Local helioseismology has detected spatially extended converging
surface flows into solar active regions. These play an important role in
flux-transport models of the solar dynamo.
  Aims. We aim to validate the existence of the inflows by deriving horizontal
flow velocities around active regions with local correlation tracking of
granulation.
  Methods. We generate a six-year long-time series of full-disk maps of the
horizontal velocity at the solar surface by tracking granules in continuum
intensity images provided by the Helioseismic and Magnetic Imager (HMI) onboard
the Solar Dynamics Observatory (SDO).
  Results. On average, active regions are surrounded by inflows extending up to
10 deg from the center of the active region of magnitudes of 20-30 m/s,
reaching locally up to 40 m/s, which is in agreement with results from local
helioseismology. By computing an ensemble average consisting of 243 individual
active regions, we show that the inflows are not azimuthally symmetric but
converge predominantly towards the trailing polarity of the active region with
respect to the longitudinally and temporally averaged flow field.
