I like maps and have a lot of fun with Neighborhood Knowledge of California and the charts and maps you can produce based on 2000 Census data.
According to the Census, Latinos make up a plurality (thanks to CD for the correction) of both the county (44.56%) and city of Los Angeles (46.53%). I’m sure I don’t have to tell you in which communities Latinos are most highly concentrated (just think of the place most divided up by freeways). Unincorporated East LA has the highest population percentage of Latinos in the US with about 96%. I guess that will soon be changing.
Key to the Map
Orange 0%-25% Latino