  Context: The detection of gamma-rays in the very-high-energy (VHE) range (100
GeV-100 TeV) offers the possibility of studying the parent population of
ultrarelativistic particles found in astrophysical sources, so it is useful for
understanding the underlying astrophysical processes in nonthermal sources.
Aim: The discovery of the VHE gamma-ray source HESS J1507-622 is reported and
possibilities regarding its nature are investigated. Methods: The H.E.S.S.
array of imaging atmospheric Cherenkov telescopes (IACTs) has a high
sensitivity compared with previous instruments (~1% of the Crab flux in 25
hours observation time for a 5 sigma point-source detection) and has a large
field of view (~5 deg in diameter). HESS J1507-622 was discovered within the
ongoing H.E.S.S. survey of the inner Galaxy, and the source was also studied by
means of dedicated multiwavelength observations. Results: A Galactic gamma-ray
source, HESS J1507-622, located ~3.5 deg from the Galactic plane was detected
with a statistical significance > 9 sigma. Its energy spectrum is well fitted
by a power law with spectral index \Gamma = 2.24 +/- 0.16_{stat} +/- 0.20_{sys}
and a flux above 1 TeV of (1.5 +/- 0.4_{stat} +/- 0.3_{sys}) X 10^{-12} cm^{-2}
s^{-1}. Possible interpretations (considering both hadronic and leptonic
models) of the VHE gamma-ray emission are discussed in the absence of an
obvious counterpart.
