  We present the Australian Square Kilometre Array Pathfinder (ASKAP)
observations of the Galaxy and Mass Assembly (GAMA)-23h field. The survey was
carried out at 887.5 MHz and covers a 83 square degree field. We imaged the
calibrated visibility data, taken as part of the Evolutionary Mapping of
Universe (EMU) Early Science Programme, using the latest version of the
ASKAPSoft pipeline. The final mosaic has an angular resolution of 10 arcsec and
a central rms noise of around 38 $\mu$Jy beam$^{-1}$. The derived radio source
catalogue has 39812 entries above a peak flux density threshold of 5$\sigma$.
We searched for the radio source host galaxy counterparts using the GAMA
spectroscopic (with an i-band magnitude limit of 19.2 mag) and multi-wavelength
catalogues that are available as part of the collaboration. We identified hosts
with GAMA spectroscopic redshifts for 5934 radio sources. We describe the data
reduction, imaging, and source identification process, and present the source
counts. Thanks to the wide area covered by our survey, we obtain very robust
counts down to 0.2 mJy. ASKAP's exceptional survey speed, providing efficient,
sensitive and high resolution mapping of large regions of the sky in
conjunction with the multi-wavelength data available for the GAMA23 field,
allowed us to discover 63 giant radio galaxies. The data presented here
demonstrate the excellent capabilities of ASKAP in the pre-SKA era.
