The Dunston family sailed to America in 1849 on the ship Ashland. The ship manifest shows their surname as "Dunasan."
At the time of the 1850 federal census, Maria was living with her sister and brother-in-law and their children. The Cummings Company records indicate that John Broom (Maria's brother-in-law) was part of that company and that he was in a traveling group of five people. It is likely the same five people that were in his household at the time of the census: himself, his wife, his two children, and Anna Maria.
Her name is shown as "Anna Maria Christensen" on her death certificate.