How far did Blues music spread?

How far did it spread geographically?

the entire united states (of course)...canada...and into europe...australia, as well...

you don't hear anything about blues artists from south america or asian countries; but i'm sure you have fans of blues music in those countries as well...

I know it spread to Europe in the sixties. All the old Chess artist played there on tours after the blues died out in the early sixties here in the U.S. The Stones, Animals, Yardbirds, Bluesbreakers, and Led Zep were heavily influenced. Sonny Boy Williamson once said that those English boys want to play the blues badly and they do. The Animals and Clapton both backed him on his tours. He had even planned on moving there due to his popularity there but passed away before he could. Check out Bring It On Home by Sonny Boy and written by Willie Dixon. Led Zep did it on their second album and took credit for it until sued.

World wide.

Say, for instance, Argentina. A very popular band in that country is "La Mississippi".

all over the world.

Corrosion & Scapegoat are correct. The Blues diaspora is global. Everyone from Hawaiian slack key guitarists to Bob Marley, to Joseph Spence to french chanson singers has been influenced by the blues. In an ironic twist, even west african musicians have been influenced by a music that is largely derived from west african roots.

It spread to London, England .

it spread from its African roots into the US and also into the rest of the world.
we in Europe have a lot of Blues Bands, I know some in Russia,Romania, Bulgaria,Australia,Brazil,Argentina and a lot of Bands in Nigeria,South Africa.