The woman is a resident of Umeå and has reported missing.
Police believe she disappeared in a red Volkswagen Fox.
"All observations of the car are important and it may have traveled far and not only in Västerbotten County," the police write on their website.
The woman disappeared from Umeå, but her phone has connected to a mast in Oxfjället in Dorotea.
The mast covers an area where, among other places, the towns of Risbäck, Rajastrand, Storbäck and Borgafjäll are located.
- We would like to receive an observation from the public so we know where to look, says Åsa Mjörndahl, the police's spokesperson in the North region.
The woman is in her 75s, is 1.67 tall and has dark short hair.
She has glasses and is leaning forward a bit, according to the police.