MARSHFIELD, WIS. — Marshfield Clinic Health System and Sanford Health have signed an affiliation agreement to create an integrated health system, officials announced Wednesday.

The organizations announced in July they had signed a letter of intent to combine. The merger is expected to close by the end of the year, subject to regulatory processes and closing conditions, the nonprofit health systems stated in a news release.

Sanford, based in Sioux Falls, S.D., and Marshfield, headquartered in Marshfield, Wis., remain two separate, independent organizations until the closing.

Marshfield is about one-fourth the size of Sanford in terms of employees. It serves 45 communities across Wisconsin and the Upper Peninsula, including Iron Mountain.

The combined system would include 56,000 employees. It would have had $10.3 billion in revenue in 2023, ranking it just outside the nation’s top 20 largest health systems, according to SiouxFalls.business.