Trespass
One issue that sometimes a person may consider if someone is coming onto or remaining on his/her property without permission is the crime of trespassing. Normally a person who has someone trespassing on his/her property may be able to contact the police to report the incident, and generally the police will make a decision about whether a crime is being committed and whether to make an arrest. In some states, there may be a requirement that the property owner first advise the person in writing that s/he has no permission to enter, and keep a copy of the writing along with notes of the date and time that the notice was given as proof that the person was notified. In other states, oral notice may be enough. I found a website with the criminal definition of trespass in STATE here: [GOOGLE CRIMINAL TRESPASS IN THE STATE TO FIND THE LEGISLATIVE WEBSITE OR ANOTHER REPUTABLE ONE TO LINK TO] A lawyer might be able to provide more specific advice on trespass in STATE. Here is a link for free legal assistance (if you qualify) and lawyer referral services in your state: LINK