Well, she was just a teeny bit anti-slavery, the main platform point of the Republican Party at the time.
Also, the fact that she bought land from GOP Senator William H. Seward in 1859 points to the fact she had at least had very friendly ties to Republican politicians themselves.
Women couldn’t vote until 1920. She died in 1913. I get the party platform angle, but I’m not sure how you can be a political party member if you can’t vote.