Crocker-McMillin Mansion-Immaculate Conception Seminary

Crocker-McMillin Mansion-Immaculate Conception Seminary is a historic seminary in Mahwah, Bergen County, New Jersey, United States. The Immaculate Conception Seminary was founded in 1861 as part of Seton Hall University. From 1927 to 1984 the seminary was located in the Crocker-McMillin Mansion. It is now again part of Seton Hall University.

It was built in 1903 and added to the National Register of Historic Places in 1997.