The fourth season of One Tree Hill began airing on September 27, 2006. The season concluded on June 13, 2007, after 21 episodes. This is the first season to air on the newly formed The CW television network. The season had a brief hiatus for three months from February 2007 to May 2007, to make their timeslot available for season eight of ANTM. The show returned May 2nd, 2007 to air the last 6 episodes of the season. This marked the first and last season of the show to air into June.