In searching for a comprehensive list of John Duncan Dunn courses, I stumbled on this thread which probably sets forth the best snapshot of his work in California. Although I wouldn't go as far as to say Dunn was responsible for the growth of the game in CA, he was certainly a key player during its boom.
C&W gives us a short list of Dunn projects, which includes:
Atascadero CC (1927, NLE)
Catalina GC (1925)
Idyllwild CC
Lake Elsinore GC (NLE)
Lake Norconian C (1928, NLE)
Los Serranos Lakes CC (North Cse 1925)
Parkridge CC
Peter Pan CC (NLE)
Rio Hondo CC
Santa Ana CC (1924)
Woodvista GC (fka Brockway GC) (9 1924)
This list is far from complete, but as updated and combined with the additional courses added below (several of which were mentioned in this thread), it demonstrates a tremendous amount of design activity in a relatively short period of time.
1919Unnamed Whittier Course (Whittier) - Sept. 26, 1919 San Francisco Chronicle notes Dunn writing he had laid out a 6,000 yard course in Whittier.
Wilshire CC (Los Angeles) - Sept. 26, 1919 San Francisco Chronicle notes Dunn writing he was to superintend work on the course.
1920Tahquitz GC (Hemet)
1922Brookside Municipal GC aka Pasadena Municipal GC (Pasadena) - Along with Walter Travis, prepared a preliminary routing for the course in the Arroyo Seco before project eventually went to William Bell Sr. Dunn's work began here in 1919.
Nov. 9, 1923 Los Angeles Times -
Lake Tahoe CC (Lake Tahoe)
Western Avenue GC (Los Angeles)
March 12, 1922 Los Angeles Times -
Coyote Pass Project (Los Angeles) - Oct. 8, 1922 Los Angeles Times notes plans for three public courses to be built by Dunn between Los Angeles and Pasadena. No evidence project ever came to pass. Possible that this was in reference to the Pasadena Municipal project.
1923Santa Ana CC (Santa Ana)
Sept. 25, 1923 Santa Ana Register -
Woodvista GC fka Brockway CC (Brockway)
1924Big Bear Lake G&CC aka Bear Valley CC (Pine Knot)
Lake Elsinore GC (Los Angeles)
Parkridge CC (Corona)
Dec. 10, 1924 Los Angeles Times -
Rio Hondo CC (Downey)
Sept. 22, 1924 Los Angeles Times -
Woodland Hills CC fka San Fernando Valley CC fka Girard G&CC (Woodland Hills)
La Quinta Country and Golf Club (Santa Susana) - June 1, 1924 Los Angeles Times notes Dunn engaged to build the course. No evidence course was ever built.
Los Serranos Lakes CC (North) (Chino) - Also remodeled parts of the course in 1927.
Feb. 10, 1924 Los Angeles Times -
March 27, 1927 Los Angeles Times -
Sepulveda CC (Los Angeles) - Dunn was originally hired to design the 18 hole course before the contract went to William Bell Sr.
July 22, 1924 Los Angeles Times -
1925El Merrie Del CC (Sunlands)
May 10, 1925 Los Angeles Times -
Fairmede GC (Oakland)
Dec. 14, 1924 Oakland Tribune -
Idyllwild CC (Idyllwild)
June 14, 1925 Los Angeles Times -
Mayberry G&CC (Whittier)
May 6, 1925 Los Angeles Times -
Santa Catalina Island GC (Catalina Island)
Glendora Golf Course (Glendora) - May 26, 1925 Los Angeles Times notes plans for Dunn to build a course in Glendora. No evidence course was ever built.
1926Acacia CC fka Temple CC (San Dimas)
Atascadero CC (Atascadero)
June 28, 1927 Los Angeles Times -
Black Jack Island GC (Catalina Island)
Dana Point Yacht and CC (Los Angeles)
March 19, 1925 Santa Ana Register -
El Sereno CC (Los Angeles/NLE)
Aug. 8, 1926 Los Angeles Times -
Briar Cliff CC (San Fernando Valley) - Oct. 17, 1926 Los Angeles Times notes course being laid out by Dunn. No evidence course was ever opened.
Shoreacres Club (Mexico) - June 6, 1926 Los Angeles Times notes Dunn designed and laid out two courses, which were located on the beach 20 miles south of San Diego.
1927Baywood CC fka Laurolawn CC (Hayward)
Oct. 8, 1927 Hayward Daily Review -
Cave Landing CC (Pismo Beach) - Planned to be a George Thomas, Peter Cooper Bryce, Alister MacKenzie collaboration. No evidence course was ever built.
Jan. 30, 1927 Los Angeles Times -
Gleneagles GC (Pierson Ranch)
May 15, 1927 Los Angeles Times -
Golfers' CC (Calabasas)
May 1, 1927 Los Angeles Times -
1928Lake Norconian Club (Norco/NLE) - 18 hole course.
Aug. 4, 1928 Santa Ana Register -
1929Brae Mar Public GC (Santa Monica/NLE) - 18 hole Par 3 Course
June 30, 1929 Los Angeles Times -
New Course at Big Bear Lake (Big Bear Valley) - March 9, 1929 San Bernardino Sun reported plans for a new course to be laid out by Dunn. No evidence course was ever built.
Date UnknownPeter Pan CC - Course was located at Big Bear, not sure which Big Bear course (1924 or 1929) this one was.