From the shore in Orange County (CA) nearest me, it's about 33 miles over to Catalina Island. (The song lyric "26 miles across the sea ..." refers to the distance from the LA / Long Beach harbors). It rained overnight, so it's cloudy, but you can see the outline of Catalina just below and to the right of the sun in this late-afternoon photo today.

See also the map (for orientation; I'm just north of "Dana Point" on the map) and a stock photo pic of the "Casino" at Avalon Bay. It's only a casino in the Italian definition of an entertainment building along the shore. Built in art deco style, its heyday was during the 1940's big band era.

BTW, the island further south is San Clemente Island, still used by the US Navy occasionally for live-fire ship to shore practice. Needless to say, it's off limits to civilians!!