How can I look up ADN or AS schools for RN by state and city?

Most state BON websites, as far as I know, include a list of all the nursing programs in the state approved by the BON, typically broken down by type of program (LVN/LPN, ADN, BSN, etc.). That would be one way to go, starting with the states you're most interested in.

Check each state's Board of Nursing (BON) or Board of Registered Nursing (BRN) website. In California it's the BRN.