Hailey Dunbar-Blanchette, 2, was taken from a residence in Blairmore, Alta., around 3:30 a.m. Monday, according to Crowsnest RCMP.
An Amber Alert was issued in Alberta on Monday afternoon and later extended to B.C., Saskatchewan, and south of the border in Montana.
Dunbar-Blanchette is described as a two-year-old white girl with a small build, brown eyes and light brown hair with bangs.
RCMP Supt. Tony Hamori told reporters Tuesday afternoon a 22-year-old male was arrested earlier in the day in Blairmore. The suspect has not been charged.
Hamori also said that Hailey remains missing and that the Amber Alert will be renewed.