My mother has recently passed away. Months ago she told me she opened an Irrevocable Trust in my name, and one for my sister as well. I can not locate any paperwork and went to 2 local banks that she used, and have had no luck finding these accounts. I know they were opened within the year so she has not received the 1099 from the IRS yet. Is the 1099 my only way to locate the accounts? What will the 1099 tell me (what bank they were issued from)? Is an Irrevocable Trust something she could have opened online or would that be done in person? Any advice how I go about locating these accounts with nothing to work from?

An irrevocable trust is a legal instrument - she must have worked with an attorney to set it up. So if you know who her attorney was (probably the same one who wrote her will) you can start there. Then to fund it, she would have established account(s) in the name of the trust. I would expect that she would be receiving monthly account statements - so keep an eye on the mail and see if anything comes in. And one minor correction - the 1099 will come from the financial institution, not the IRS.