To be a criminal a person has to do something criminally wrong. We do not penalize first time illegal entrants as criminals. Only those who are deported and return illegally are criminals when they arrive.
I am a pretty smart guy, but I do not know everything. My answers here come from the knowledge I carry around in my head--if you want me to look something up, you should come see me. Take any advice here as being general in nature. Please be careful with your life and make decisions that are smart.
There is a distinction between people who enter without inspection and those who overstated a visa. For example, It does not matter if you overstay a visa and then apply for a green card through marriage. However, if you entered without inspection, you would have to apply for a waiver.
Federal immigration law is administrative law. Admin, licensing regulations are distinct & different from criminal statutory violations. Violations of federal immigration laws are violations of administrative laws. Administrative violations are not designed to punish criminal conduct although we see immigrants treated very much like criminals. Generally, immigration violations are not dealt with in the criminal judicial system. However, federal criminal laws do punish illegal re-entry (felony) and first time entry without inspection (petty misdemeanor) as criminal violations. Previously, immigration violations were not criminalized to this extent. Laws under IIRIRA have increased the criminalization of immigrants.
The answer is "it depends." Illegally staying in the country is not a criminal offense. If it were the accused would have a right to an attorney and the "innocent until proven guilty" rule would apply. Most people who stay illegally are guilty of a CIVIL offense. However, illegally entering after a prior removal is a criminal offense (a felony.)
Dhenu Savla, Esq.
This answer does not create an attorney-client relationship and is not meant to be relied upon as legal advice.