=LOOKUP(99^99,Sheet1!A:A)

Where Sheet1 is the name of the sheet containing data in column A - will
return the last value in the column.

"SMH" wrote:

Within one workbook, I'm trying to have one tab read off another using a
formula. I need the "Summary" tab to display the last cell with data (not
null) in a particular column. For example, column A has data populated from
A2:A50, I want to show A50. Any suggestions?