Legal Question in Employment Law in Maryland

You would need to be more specific (are there written contract terms?), but typically, yes, an employer can require that you give 4 weeks notice before you leave. It's called a "Garden Leave Provision" if you want to google it. If your employer insists on it, there are things you can demand in return. Consult a lawyer.

Best of luck.*****The above is for informational purposes only and does not create an attorney-client privilege.*****