You can use cell borders for this.
Step 1: turn off Gridlines on the View tab of the ribbon.
Step 2: select the range that you want to have visible gridlines.
Click the dropdown arrow on the right hand side of the borders button in the Font group of the Home tab of the ribbon.
Select More Borders... from the dropdown menu.
Select the thin continuous line.
Select a color - if you want the lines to look like the built-in gridlines, choose a medium gray.
Click both Outline and Inside.
Finally, click OK.
