The Historical Society office is open year round, Monday through Friday from 9:00 a.m. until 4:30 p.m. We are closed most state and federal holidays. Please contact us by phone at (815) 923-2267 or email at info@mchsonline.org if there is any uncertainty.

The Research Library is accessible by appointment only. Walk-ins cannot be accommodated no matter what the circumstances or the distance traveled. Please understand that we are a nonprofit organization with a small staff trying to do many things, often simultaneously. You must call to make any library appointments at least 24 hours in advance and please note that that does not necessarily mean that we will be able to get you on the schedule within 24 hours but we will do our best. The library hours are Monday through Friday, 9:00 a.m. to 4:30 p.m. year round. There is a fee for use by non-members.

We occasionally offer evening and Sunday hours without an appointment. Members of the McHenry County Illinois Genealogical Society staff the research library at those times. Please refer to the "Calendar of Events" web page for dates and times. For more specific research library usage and fee information, please go to the "Research Library" web page.

The Museum is open May through October, Tuesday through Friday from 1:00 pm. until 4:00 p.m., and Sunday from 1:00 p.m. until 4:00 p.m.   The museum is occasionally open during special programs in the evenings or weekends. For those dates, please click on the "Calendar of Events" link on our home page.