A woman missing for more than a week was found alive, having been stuck in the mud in a state park for at least several days, US police in Massachusetts said Tuesday.

Emma Tetewsky, 31, was found in a swamp-like area in Borderland State Park after hikers heard her cries for help, a joint statement from local authorities involved in the rescue said.

She had been last seen just outside the park, about 30 miles (50 km) south of Boston, on June 25.

The mucky conditions at first kept rescuers at bay, necessitating the use of all-terrain vehicles.

Upon their arrival to the heavily wooded park, officers from the nearby town of Easton "waded 50 feet from the shore, through thick brush and swamp, to reach Tetewsky," the statement said.

The officers "blindly jumped into the water and followed the woman's calls for help," Easton Police Chief Keith Boone said.

It is believed Tetewsky may have been trapped in the mud for at least three days, the joint statement added.

Tetewsky was transported to a hospital with serious injuries, although police said they did not appear to be life-threatening.