Here is a recording by famous Country/Western singer Gene Autry:

http://www.jukebo.com/gene-autry/music-clip,red-river-valley,xssl38.html

Now, many American folk singers used to modify existing songs when they played them. Some even used older tunes for their own work.

This song, "Can I Sleep In Your Barn Tonight Mister" uses the tune of "Red River Valley"

http://www.countryblaze.com/charlie-poole-can-i-sleep-in-your-barn-tonight-mister-video_30d183146.html

There is a song that I have liked for years, called "Can I Sleep in Your Arms Tonight Lady". Sorry I couldn't find a video of it to post here. Anyway, upon listening to "Can I Sleep in Your Barn Tonight Mister" I realized that both songs are related. They have some similarities in their lyrics, and both use tunes based on "Red River Valley"!

Today, I learned of potential links between two very famous American songs (or at least they are famous here in the U.S.)

It all seems to have started with a song called "Oh My Loving Brother" and "When the World's on Fire"

Here is a recording by a group called The Carter Family, who were popular in the 1930s:

http://www.dailymotion.com/video/xtxjrv_the-carter-family-when-the-world-s-on-fire-remastered-country-music-experience_music

They then wrote their own song, with a tune based on "When the World's on Fire". It's called "Little Darling, Pal of Mine"

http://www.jukebo.com/the-carter-family/music-clip,little-darling-pal-of-mine,xssfr8.html

In the 1940s, a singer named Woody Guthrie wrote his own set of lyrics to a tune partly based on one of those songs, and called it "This Land is Your Land". It went on to become popular in the 1960s.

http://vimeo.com/50634284

Now, this is a bit of a stretch, but when I was listening to "Little Darling, Pal of Mine" this afternoon, the melody of the last line reminded me of a song I have known since I was a kid. It's also pretty famous here in the US. The connections seem fairly tenuous, but some other people think they are there (I checked online to make sure I'm not crazy).

http://www.dailymotion.com/video/xttxag_gene-autry-you-are-my-sunshine-remastered-country-music-experience_music

If you have difficulty accessing any of the websites, please tell me in the comments!