How do I extend worksheet to 1 million rows?

I have a worksheet that was originally saved as a xls (2003) file. I have resaved it as a xlsx (2007) file, but the max rows are still at 65,536. I am trying to combine over 100,000 records into one sheet.

The only way I have been able to create a excel document with more than 65,536 rows is to export my records from an Access file.

I am working in compatibility mode.

Is there a way I can extend the limit in my existing xlsx file to a million rows?

Thanks.