Can I travel outside the U.S. while my green card application (I-485) is pending?

Generally, no — not without approved advance parole (Form I-131) first. Leaving the U.S. while your I-485 is pending, without that document already in hand, can be treated by USCIS as abandoning your application in many situations.

There are exceptions: if you already hold a valid H-1B, H-4, L-1, L-2, or certain other specific visa categories, you may be able to travel and return without it counting as abandonment — but this is genuinely case-specific, so it's worth confirming your exact situation rather than assuming.

If you do have approved advance parole, remember it allows you to be considered for re-entry — a CBP officer still makes the final admission decision at the border, so it isn't an absolute guarantee.