Harriet Ballantyne will be running the Shropshire Way next week to raise money for Shrewsbury Ark.
She will complete the course over six days and will average 23 miles a day.
The keen runner is setting off on her fundraising trip on Monday and aims to complete her trip within the week by trail running one marathon a day.
The 25-year-old, who works for an environmental consultancy, said: "I've lived in Shropshire for most of my life. I am born and bred in Shrewsbury and north Shropshire, and I've moved back since finishing university but I know so little of this beautiful county, so I thought it high time I see some more.
"I decided it would be a great idea to do the long-distance walking route of the Shropshire Way. But I love to trail run, so I thought, you know what, I'll run it instead.
"I will be starting out from Shrewsbury and will be making my way along the Shropshire Way by going over the Stiperstones to Clun and Ludlow, the Clee Hills and Much Wenlock then on to The Wrekin, Ironbridge and Wem before coming back to Shrewsbury.
"I have decided to raise money for Shrewsbury Ark although I have no link with them at all.
"I just thought it would be nice to raise money for something local.
"I had the interest to do it anyway. Shrewsbury Ark is a fantastic local cause that works with the homeless and vulnerable in our community, from a cup of tea and a plate of hot food, to one-on-one sessions that help to find the services people need to make those initial changes."