General :: Find/search Root Partition ONLY?

Say I need to do: find / -name somefile.txt

And say root partition / is mounted on /dev/sda5; however, let's say I also have 250GB partitions (/dev/sda6, /dev/sda7) mounted in /media - AND another location that I cannot currently remember. Say, also, that I know the file I'm looking for is on /dev/sda5.

Obviously, the above command will also descend in /media and that other directory which represent the big partitions, wasting time in looking for the file in the wrong place.

Is there a way to instruct find (or other command) to search only / on /dev/sda5, and NOT to descend to directories if they are on different partitions ?