Assuming that your daughter has never paid rent, you could certainly argue that she is now a mere trespasser and order her to leave. If she refuses to do so, you could call the police and ask them to put her out and charge her with trespassing. However, I think that most officers would tell you this is a civil matter and that they will not arrest your daughter for trespassing, even though technically they might be wrong.
A more reasonable option would be to treat her as a tenant holding over: Write her a 30-day letter and, if she refuses to leave, file an appropriate action in landlord-tenant court.
A third option, and perhaps the safest, would be to retain legal counsel to write your daughter for you and, if necessary follow up with a landlord-tenant action or, if the circumstances warrant, a complaint for trespassing. Personally, I would do everything possible to force your daughter to leave voluntarily or, even better, convince her that she needs to start supporting herself and not just mooch off mom. It's called tough love.
I do not practice in MD, but I may offer some general advice. If your daughter refuses to leave at your request, you will likely need to evict her formally. This may involve a court action.
Consult with a local attorney experienced in eviction matters for more specific advice.