How does one find out what a payer's state no. (line 11 of form 1099-R) is? The 1099-R instructions say, "The state number is the payer's identification number assigned by the individual state." What is the process by which an individual state assigns the number? Does the payer apply for a number (similar to applying for a federal EIN)?

short answer is yes, plan registers with state for withholding purposes and will be assigned a number.

My group at the bank I recently left was responsible for this for the trusts which the bank was trustee.