"Nigger, don't let the sun set on you here!" signs are an oft-asserted
example of openly racist segregation. All my life I have heard abut
these signs in places like Tennessee, Georgia, Alabama and even the
Klan conclaves in Indiana. But when I asked my older relatives, none
of them could name an instance when they'd actually seen a sign like
that themselves -- although they all believed they were real. But I
have my doubts.

Please find authentic photographs of such a signs from a recognized
academic or historical source.

Cites, weblinks, magazine and book resources welcome.

The same issue is being discussed here. You might find this interesting:

http://www.dallashistory.org/cgi-bin/webbbs_config.pl?read=5272

Regards;
tutuzdad-ga

There was once a sign in Whitesboro, Texas that said:

"If your skin is black, let the sun set on your back, leaving Whitesboro."

There are several online references to so-called "sundown laws" that
prohibited African-Americans from spending the night in certain areas:

://www.google.com/search?hl=en&q=%22sundown+law+OR+laws%22