Hi,
Do you know what year Catherine was born? Are you sure they were married when she emigrated? If yes, did they have any children born in Sweden and if so, what where their names and date of birth?
I found this woman on the Swedish emigration DVD "EMIBAS" but she isn't married and she is heading for Minnesota:
Christina Kathrina Ehn, b. 3 AUG 1850 in Hudiksvall, Gävleborgs län, Hälsingland. Emigrated 3 AUG 1872 from Hudiksvall, Hudiksvall, Gävleborgs län, Hälsingland. Going to Minneapolis, Minnesota
Could that still be a match?
Let me know and I'll have a look.
Anna