The first floor of the Lambert Castle Museum contains historical period rooms that interpret the Castle’s past as the home of Catholina Lambert, one of nineteenth century Paterson's most prominent silk textile manufacturers.   These rooms incorporate many of Lambert's original possessions as well as other historical items from the PCHS collections.  Volunteer docents regularly provide museum visitors with a guided tour of the the first floor rooms and explain the Castle's history within the context of Paterson’s tangled social and industrial past.

Complementing the period rooms, the second floor of Lambert Castle Museum features several long-term exhibition galleries: folk art gallery; "Curiosities From The Collections" gallery; Julian Rix (prominent local artist) gallery; Great Falls gallery; portrait gallery; and local history gallery.  Museum visitors may enjoy a short video presentation about Paterson's historical development in the local history gallery.

The third floor of Lambert Castle Museum is the site of featured exhibitions that change on a regular basis, usually three times each year (winter, spring and summer/early autumn).  These exhibitions provide visitors with the opportunity to view historical artifacts from the extensive collections held by PCHS.  This gallery also serves as a venue for various Passaic County cultural organizations to present exhibitions and programs about their own histories and traditions.