In 1930, and even in 1906, it's a good-sized country. We need some more clues -- any mention of a family village? Is the village mentioned in the immigration records? Can you point us to a ship's list in Ancestry? (For 20th century immigration, the records seem to list the town of origin, but I cannot find a match.) Do you have church baptismal records from here in the states that might mention the place of birth of the parents?
Technically, in 1930, it was still Czecho-Slovakia. Before World War I, it would have been Bohemia, Moravia, and Slovakia, etc. If you are lucky enough that they were from Moravia, chances are better that you can find them.