The structure for Little League Baseball's international tournament playoff system in California has changed several times since California's district structure was implemented in 1958. Key events in the evolution of this structure include the following:
| YEAR | MILESTONE |
| 1957 | All California leagues compete for berths in a single, four-team state tournament. |
| 1958 | California is organized into 33 districts that are numbered sequentially from north to south. The 33 district champions compete for the right to enter a four-team, single-elimination state tournament. |
| 1959 | Five new districts are created:
District 34 (Visalia/Tulare area) is spun off from District 10
District 35 (Santa Rosa/Ukiah/Fort Bragg area) is spun off from District 4
District 36 (Palos Verdes/Manhattan Beach area) is spun off from District 25
District 37 (Inglewood/Hawthorne area) is spun off from District 26
District 38 (Long Beach area) is spun off from District 27
Additionally, for the first time, California holds separate divisional tournaments that crown champions of Northern and Southern California. Both divisional champions advance directly to the West Region Tournament. Through the 1970 tournament season, both the Northern California and the Southern California divisional tournaments are four-team, single-elimination tournaments. |
| 1960 | District 9 elects to not participate in the international tournament (it would return in 1970). Additionally, ten new districts are created:
District 39 (Santa Cruz/Watsonville area) is spun off from District 9
District 40 (Granada Hills/Northridge area) is spun off from District 14
District 41 (El Cajon/La Mesa area) is spun off from District 31
District 42 (Chula Vista area) is spun off from District 33
District 43 (San Bernardino area) is spun off from District 22
District 44 (Sunnyvale/Santa Clara area) is spun off from District 12
District 45 (Hayward/Union City area) is spun off from District 4
District 46 (Anaheim/Fullerton area) is spun off from District 30
District 47 (Chico/Oroville area) is spun off from District 2
District 48 (Alturas/Susanville/Quincy area) is spun off from District 2 |
| 1961 | Three districts are created and one is dissolved:
District 49 (Hesperia/Apple Valley/Barstow corridor) is spun off from District 22. District 22 is eliminated, and its remaining leagues are placed in Districts 43 and 24
District 50 (Lompoc/Santa Maria/San Luis Obispo area) is spun off from District 13
District 51 (Lancaster area) is spun off from District 16 |
| 1964 | District 22 (Brawley/El Centro area) is spun off from District 43 |
| 1966 | Five new districts are created:
District 52 (Palo Alto/San Mateo area) is spun off from District 11
District 53 (Cupertino/Los Altos area) is spun off from District 44
District 54 (Roseville area) is spun off from District 5
District 55 (Mission Viejo/Huntington Beach area) is spun off from District 30
District 56 (Fullerton/Yorba Linda area) is spun off from District 29 |
| 1967 | District 57 (Danville/Pleasanton area) is spun off from District 45 |
| 1968 | District 58 (Banning/Cathedral City/Blythe area) is spun off from District 43 |
| 1970 | District 9 returns to the international tournament.
Additionally, District 59 (San Jose area) is spun off from District 12 |
| 1971 | Four new districts are created:
District 60 (Hacienda Heights/La Puente area) is spun off from District 20
District 61 (Bakersfield area) is spun off from District 34
District 62 (Huntington Beach area) is spun off from District 55
Additionally, the Southern California tournament structure is altered, as the SoCal tournament structure encompasses eight sectional tournaments instead of the previous four. Each sectional champion then competed in a one-game playoff against another sectional champion to determine the four divisional tournament respresentatives. |
| 1972 | All California leagues competed for a single state championship in 1972, instead of separate Northern and Southern California tournaments. Four of the twelve sectional champions advanced directly to the state tournament, while the remaining eight competed in one-game playoffs for the four remaining slots. |
| 1973 | District 53 is reconfigured. Leagues in the old District 53 are placed in Districts 11 and 52. A new District 53 (Vallejo area) is spun off from District 4. Additionally, District 13 crowns champions for District 13A and 13B; both champions advance to sectional tournament competition.
California retained its eight-team, single state champion format in 1973, but organized districts into eight sections rather than twelve. |
| 1974 | District 63 (Santa Barbara area) is spun off from District 13.
California reverted to the practice of crowning separate Northern and Southern California champions. Both the North and the South were divided into four sections, and the state held a pair of four-team, single-elimination tournaments. |
| 1976 | The Southern California tournament structure is expanded to include eight sections. All eight sectional champions advance directly to the state tournament. |
| 1981 | Northern California continues to hold a four-team state tournament; however, after single-elimination semifinal round games, the two finalists were to meet in a best 2-of-3 playoff to determine the NoCal champion. |
| 1982 | The Northern California tournament structure is changed to a four-team, double-elimination event. |
| 1983 | District 11 is dissolved, and its leagues are placed in Districts 52 and 44. Sometime between 1984 and 1988, Districts 26 and 28 are also dissolved. District 26 leagues are placed in District 36, and District 28 leagues are placed in District 37. |
| 1985 | The Northern California tournament structure is changed to a five-team, double-elimination event. |
| 1986 | Southern California changes its divisional tournament format to an eight-team, double-elimination competition. |
| 1987 | District 14 is dissolved, and its remaining leagues are placed in District 40 |
| 1989 | District 15 is dissolved, and its remaining leagues are placed in District 40 |
| 1992 | Two new districts are created:
District 11 (Rocklin area) is spun off from District 54
District 28 (Oceanside/Temecula area) is spun off from District 31
Additionally, the Northern California tournament structure is expanded to a six-team, double-elimination format. |
| 1993 | District 15 (Amador and Calaveras County area) is spun off from District 8 |
| 1994 | District 14 (Fremont/Newark area) is spun off from District 57 |
| 1996 | Two new districts are created:
District 26 (Humboldt and Del Norte County area) is spun off from District 1
District 64 (Davis/Vacaville area) is spun off from District 53
|
| 1998 | District 65 (Santa Maria/Lompoc area) is spun off from District 50 |
| 2001 | Both Northern California and Southern California are assigned to the West Region as part of Little League Baseball's expansion of the World Series from eight to sixteen participants.
Also in 2001, District 66 (San Diego County - South Bay area) is spun off from District 42. The new district spurs officials to realign Southern California's districts into a new set of sectional groupings. |
| 2002 | The Southern California tournament uses a pool play format. The top team in each pool following round-robin play advances to the tournament championship game. The tournament reverts to a double-elimination format again in subsequent years. |
| 2004 | District 67 (Tracy/Manteca area) is spun off from District 8 |
| 2005 | District 68 (Southern Orange County) is spun off from District 55 |
| 2007 | Two new districts are created:
District 70 (Oceanside/Vista area) is spun off from District 28
District 71 (Fontana/Rancho Cucamonga area) is spun off from District 21
|
| 2008 | District 72 (Corona / Western portion of Riverside) is spun off from District 24 |
| 2010 | District 60 (La Puente / Hacienda Heights area) is dissolved, and its remaining leagues are placed in Districts 19 and 20
Also in 2010, District 50 (San Luis Obispo area) is dissolved, and its remaining leagues are placed in District 65 |
| 2012 | District 73 (San Jouquin Valley - Northern portion) is spun off from District 10 |