On the bottom of a check or your bank's online checking account.
Your routing number is the farthest left grouping of numbers, usually under “FOR_________” or “MEMO_________.”
Your account number is the grouping of numbers immediately after your routing number, under where you sign. It usually starts with a 1, followed by a bunch of 0's, and finishes with your account number.
(Ex. 100000008547362 then “8547362” would be your account number)