* Pennsylvania State University (PSU): While not directly in Harrisburg, Penn State's main campus in University Park, PA, offers a highly-regarded architecture program. This is probably your closest option for a full, accredited program. It's a significant drive, however.
* Other Schools Further Away: Depending on your definition of "near," you might consider schools in Philadelphia (University of Pennsylvania, Drexel University) or potentially even further afield in New York or Washington D.C. These are all significantly further than Penn State, though.
To find the best fit, I recommend checking the websites of the schools mentioned above to verify program details and distance. You could also search for "accredited architecture schools near Harrisburg PA" online to find other possibilities and compare them based on your specific needs and preferences.