I entered the U.S. as a permanent resident two months ago, but I have still not received my U.S. green card. I'd like to take a trip back to Pakistan to see my family. What can I do to make sure I'm allowed back in to the United States?
Some people wait many weeks or even months for their green cards. However, your lack of an actual green card shouldn't stop you from traveling.
When you entered the U.S. as a permanent resident, you should have been given a stamp in your passport to show your new status. Double check your passport to make sure, but they're unlikely to have forgotten.
The stamp in your passport will have an expiration date on it, which is usually six months from when it was placed there. As long as the expiration date hasn't passed, and won't pass while you are away from the U.S., you are free to travel.
If they did forget, or if the stamp is going to expire before your return from traveling, get in touch with the USCIS Contact Center. The officer there should be able to tell you what's taking so long to get you your green card, and also make an appointment to go to the nearest office of U.S. Citizenship and Immigration Services or USCIS. Take your passport, along with any other form of ID you might have and your immigration paperwork. USCIS should be able to stamp your passport during your visit.
Here are a couple of other useful precautions: Check the expiration date on your passport itself. If your passport will expire while you're away, get a new one. But make sure you don't have to give the old one up. You will need to carry both the old and new passport with you, since the old one has your permanent residence stamp.
Also, leave a photocopy of your passport and permanent residence stamp with someone who will be in the U.S. while you are away, in case your passport gets stolen or lost. If it is, you'll need to get a new one, then go to the nearest U.S. consulate to get a new permanent residence stamp for U.S. entry. Having a fax or scanned email with a copy of your permanent residence stamp will help enormously.
One last thing to remember: You shouldn't stay outside the U.S. for more than six months, or do anything else to indicate that your true intent is to live outside the United States. People can lose their permanent residence by "abandoning" it. For more information on traveling as a green card holder, see Nolo's articles on, "After Getting Your Green Card: How to Keep It."