My Great Grandfather and his family listed Hungary as place of Origin
in the 1910 census, but list Austria in the 1920 census. Can anyone
explain?

MODERATOR NOTE: You may also want to ask questions about this
geographical area in the relevant JewishGen Special Interest Groups
(SIGs), in this case the Hungarian SIG and the Austria-Czech SIG. For
further information, go to the JewishGen home page, www.jewishgen.org,
and under "SIGs" select these groups.