U.S. Sen. Jon Kyl plans to donate historical materials and papers collected during his time in Congress to his alma mater, the University of Arizona.

Kyl's office says he'll visit the university's main campus in Tucson on Wednesday to announce the donation to the university library.

Kyl is retiring after serving nearly 18 years in the Senate. Before that he was a U.S. representative for eight years.

The Arizona Republican received both his bachelor's and law degrees from the University of Arizona