Context : Cam OB3 is the only defined OB association believed to belong to the Outer Galactic Arm or Cygnus Arm .
Very few members have been observed and the distance modulus to the association is not well known .

Aims : We attempt a more complete description of the population of Cam OB3 and a better determination of its distance modulus .

Methods : We present uvby photometry of the area surrounding the O-type stars BD $ +56° $ 864 and LS I +57 \degr 138 , finding a clear sequence of early-type stars that define an uncatalogued open cluster , which we call Alicante 1 .
We also present spectroscopy of stars in this cluster and the surrounding association .

Results : From the spectral types for 18 very likely members of the association and UBV photometry found in the literature , we derive individual reddenings , finding a extinction law close to standard and an average distance modulus DM = 13.0 \pm 0.4 .
This value is in excellent agreement with the distance modulus to the new cluster Alicante 1 found by fitting the photometric sequence to the ZAMS .
In spite of the presence of several O-type stars , Alicante 1 is a very sparsely populated open cluster , with an almost total absence of early B-type stars .

Conclusions : Our results definitely confirm Cam OB3 to be located on the Cygnus Arm and identify the first open cluster known to belong to the association .