In Los Angeles our AA meeting directory says
that the first meeting in L.A. took place on
December 19, 1939 but that meeting died out.
The first meeting that lasted was started on
either the last Friday in March or the 1st
Friday in April, 1940, according to Mort
Joseph, who organized it. In a talk given
in 1975, he said he never could remember
which Friday it was. That was at the Cecil
Hotel in downtown Los Angeles, which still
exists. It was called "The Old Mother Group."
After moving to several locations, it
eventually died out too.

History pamphlet:

http://www.lacoaa.org/HOW%20AA.pdf