<Tr> <Td_colspan="2"> List of One Tree Hill episodes </Td> </Tr> <P> The sixth season of One Tree Hill, an American television series, began on September 1, 2008 and concluded on May 18, 2009 with a total of 24 episodes . This is the third season to air on The CW television network . The seasons seventh episode, "Messin' with the Kid" achieved a series high in Adults 18--34 with a 2.7 rating . </P> <P> Season six is the final season for original cast members Chad Michael Murray and Hilarie Burton . Their characters, Lucas and Peyton, leave Tree Hill with their newborn baby in the finale . </P> <P> Lucas proposes to Peyton . They decide to get married . Peyton gives Lucas the startling news that she is having his baby . Nathan tries to make a comeback in basketball, Haley has to make a decision involving her career, Brooke takes in a young girl named Sam and deals with being attacked in her own store, and Dan spends time with Jamie as he waits on a heart transplant . Meanwhile, a movie producer named Julian Baker comes to Tree Hill and wants to make An Unkindness of Ravens into a movie . </P>

When do lucas and peyton leave one tree hill