I'd like to find a generic way to specify the entire data range in a
worksheet (without knowing how many rows or columns are in the worksheet).

Is there a way to refer to the last cell in a worksheet (not just a specific
row or column)? I see how one can use GO TO... to select the last cell, but
I can't find a way to refer to the last cell in a formula.

Alternatively, is there an easy way to identify the last (rightmost)
non-blank column in a worksheet? I see how COUNTA could be used to identify
a non-blank column, but is there a way to identify the last non-blank column,
or at least the first?

Basically, I'd like to use INDEX in one worksheet to find data in another
worksheet and don't know how to specify a generic range that will work
regardless of the number of columns (the number of rows is much less
important).

Thanks in advance.