The rally is scheduled for the morning of Oct. 31 at the Kane County Fairgrounds in St. Charles. The district includes rural and suburban areas west and north of Chicago.
Underwood is a registered nurse and in a news release Biden said that in that job she's "devoted her life to serving others."
Later that day, Biden is scheduled to appear with Brendan Kelly in Southern Illinois. Kelly is the Democratic nominee running against Republican U.S. Rep. Mike Bost of Murphysboro in the race to represent the 12th Congressional District.