Where they crucified him, and two other with him, on either side one, and Jesus in the midst. Two other - Matthew and Mark in the parallel places calls them robbers or murderers; they probably belonged to the gang of Barabbas. See about the figure of the cross, and the nature of crucifixion, on Matthew 27:35 (note).
Related Commentaries of John 19:18
John 19:18
18 Where they crucified him, and two other with him, on either side one, and Jesus in the midst.