Can my company open mail addressed to me?

Basically yes. You have limited privacy rights at work, and mail sent to work would probably not entitle you to privacy. There are a lot of "immoral" things the employer can get away with. If you really feel you were wronged, you have to sometimes get a little creative, and if this means fighting fire with fire, so be it. At times like this you may wish to consider the famous story of Al Capone. He was a gangster in the 1920s, where the government was angry with him because they knew he did stuff wrong (e.g. murder, robbery) but could not get evidence to put him away to prison ON THOSE LEGAL THEORIES. What the government did was find a "DIFFERENT THEORY" and they got the result they wanted, they got justice, as they put him away for tax evasion. Now how does this story relate to you? If you can't get them for "wrongful termination", you need to look at other aspects of your job, for an opportunity to seek legal justice not on the theory that is dear to your heart, but on other issues of possible illegal misconduct: 1. Did they provide you with breaks? 2. Did they pay you properly, including any overtime? 3. Did they make you incur any expenses for work that you were not reimbursed for (e.g. uniform, special shoes, cell phone, gas, etc). 4. Did they pay you your pay check using an out of state check causing you to go to a check cashing place or incurring a fee in order to get your money? If any of these kind of things occurred you might be able to get justice against the company. Call me if you wish to discuss this. Do you have copies of your pay stub(s), check(s)? Do you have at home a copy of the employee manual?

I do not know. You have not asked a question that involves legal advise. You may want to try discussing this with your empoyer You may want to try using a different address.

Generally yes, after all if it delivered to the coma puny address they have a right to assume it is for you in your employee status.

Tough question. Arguably, this is a trespass, but it depends on how the mail was addressed, how often you receive mail there, nature of the employer's business and other factors. Why are you receiving mail at your employer's place of business?