Police say 42-year-old Kelly Robarge was last seen on Thursday. She's had no communication with family and friends since late that morning, and there's concern she has suffered serious injury or death.
State and local police agencies and the civilian search team New England K-9 Search and Rescue all have participated in searching for the missing woman.
They've searched around Robarge's home, as well as other areas of Charlestown, Claremont and Unity.
The searches have included wooded areas and areas along roadways, in addition to ponds and waterways. Searches have also been ongoing in the border towns of Vermont and along the Connecticut River.
Authorities say they're still hoping members of the public will step forward with clues.
Family and friends of Robarge are holding a candlelight vigil near her home at 6 p.m. Tuesday. It's being organized by her daughter, Gabrielle Robarge.