A "heartbroken" Clinton supporter crossed paths with Mrs Hillary Clinton, a day after the Democrat made a painful speech conceding the US presidential election to Republican Donald Trump.

Ms Margot Gerster was on a hike with her daughter on Thursday when she saw Mrs Clinton and her husband Bill walking their dogs in Chappaqua, New York, where the couple live.

She wrote about the brief encounter - and pleasant surprise - on Facebook and also shared a photo that Mr Clinton had snapped of her with his wife.

"I got to hug her and talk to her and tell her that one of my most proudest moments as a mother was taking Phoebe with me to vote for her," Mrs Gerster wrote.

The post swiftly went viral on Thursday, racking up 105,000 likes and nearly 9,000 shares.

She said Mrs Clinton thanked her and gave her a hug before the couple continued their walk.

Ms Gerster told CNN that Mrs Clinton was seemingly at peace despite her loss.

"She seemed as well as anybody could be expected after such a crazy, crazy experience."

She said she posted the photo - showing Mrs Clinton flashing a wide smile - to "make people smile".

"It was a very dark day yesterday, I just feel like the fact I ran into Hillary while I was trying to clear my head, was sort of like a hopeful sign," she said.