The last column in Excel is column XFD, which is the highest possible column number. In a single worksheet, there are 16384 columns, and this count is fixed, meaning you cant add more columns to a single worksheet. The column header "XFD" is the last column in the worksheet. To select the last column, you can click on the header of the column where you have the column alphabet, and it will select the entire column from the first cell to the last. Alternatively, you can type the column letter and row number in the address box at the top of the worksheet to access the last column. For example, typing in XFD65536 will take you to the last column in Excel.