A mysterious "woman in black" has become the focus of feverish social media speculation after being spotted walking the highways of numerous US states.

The woman, always wearing a flowing black dress and carrying a walking stick and bag, has thus far been sighted alone on busy roads in Georgia, Tennessee, Kentucky, Ohio and Virginia.

Her travels have been regularly documented in recent weeks on a dedicated Facebook page, and on Twitter using the hashtag #womaninblack.

Many claim they tried to speak to her but found she politely declined their offers of assistance.

I asked her if she needed or wanted a ride, she said no. I asked her if she wanted something to drink, she said no. I asked her what was her mission, she said just walking. She was smoking and really didn't want to talk.

Judy Shugars, Facebook

A number of rumours have circulated as to the reasons for her journey, with some claiming she is on a religious mission.

However, amid all the speculation, one man claims he has the answer to who the mystery woman really is.

Raymond Poles claims he is the woman's brother, and has identified her as Elizabeth Poles, a 56-year-old US Army veteran, mother of two and widow from Motts, Alabama.

He told Reuters Ms Poles had been receiving treatment at a Veterans Affairs hospital to help her deal with the deaths of her husband in 2008 and father in 2009, he said.

Mr Poles claimed his sister had vanished for months at a time, adding: "I wish she would come back and let us help her."

More than 25,000 people now like the Facebook page devoted to the wandering woman, the creators of which last week posted a passionate defence of their continued interest.