Monta is also a Latvia name. According to the Wiktionary, it was first recorded as a given name of Latvians in early 20th century, and derives from Latin mons ("mountain"). According to the Population Register of Latvia (PMLP) there are 1663 women in Latvia who have the name Monta.
My mother and I as well as her cousin all have this name. We were told it came from a dime back novel in which the heroine bore the name. I don't know the name of the book however.