Los Angeles
I used to live in Los Angeles (I miss it a great deal) and participated in an organization called "Club Social y Cultural Dominicano". They are headquartered in Lawndale, CA.
They have weekly picnics and baseball games at Alondra Park in Torrance, CA. They also have yearly Mother's Day, Xmas, 27th of February & other holiday events.
Sorry, I don't have their phone # and could not find it in the online yellow pages.
Perhaps when you get there you can ask around.
Good Luck