According to the State Department, it is possible to travel with an expired passport in some circumstances. If you are traveling by land or sea to Canada, Mexico, the Caribbean, or Bermuda, you can use an expired passport as long as it was issued within the last 15 years and you were 16 years of age or older when it was issued. However, if your passport has expired for more than 5 years, you will need to obtain a new one. If you are traveling by air, you will need a valid passport regardless of your destination.
You will need to renew it before you can travel. You can usually do this by mail or in person at a passport office. However, if you need to travel urgently, you may be able to get a temporary passport. This is valid for up to one year and can be obtained from your nearest consulate or embassy. Remember that even if you have a temporary passport, you will still need to renew your regular passport when it expires.