This division was created for the 1969 season when the National League (NL) expanded to 12 teams by adding the San Diego Padres and the Montreal Expos.
In the previous two seasons prior to realignment, the Cardinals, Giants, and Cubs finished 1-2-3 in the National League standings.
Sometimes, the trouble could be alleviated for them by playing some games in Chicago, St. Louis, or Pittsburgh on the same long road trips.
Beginning in mid-August the Houston Astros and the Los Angeles Dodgers started collapsing, leaving the Braves, the Reds, and the San Francisco Giants in contention.
Following a very-long hot streak in July, August, and September, the Braves clinched the divisional championship by winning their next-to-last game.
One of the main factors in the big surge by the Braves was that the slugging outfielder Rico Carty returned to the team after missing the first half of the season while he was recovering from tuberculosis.
Carty immediately resumed his starring role, adding to the powerful offensive line-up of the Braves that also featured the sluggers Hank Aaron and Orlando Cepeda and the good singles hitter Félix Millán who was on base to score a lot of runs.
This format was to be changed in 1994, though it was not carried out until 1995 due to the 1994–95 Major League Baseball strike that started on August 12, 1994.
†† – The San Diego Padres and Los Angeles Dodgers finished the 2006 season tied for first place with identical records.
By virtue of the eight-team postseason format used for that season, division runner-up San Diego (37–23, .617) also qualified for the playoffs.
* – The Colorado Rockies played the San Diego Padres in a wild card tie-breaker game after both teams finished the season with the same record, 89–73.
Those teams faced each other in the Wild Card Game to determine the final participant in the National League Division Series.