During a layover with United Airlines, the status of your checked bags depends on whether you are on a "through-ticket" (a single booking) and the countries involved in your journey. If you have a domestic-to-domestic layover (e.g., San Francisco to Denver to New York), United's ground crew will automatically transfer your bags between aircraft, and you will not see them until you reach your final destination. For international-to-domestic layovers in the United States, even if your bags are tagged to the final city, you must collect your bags after clearing immigration at the first U.S. port of entry. You then walk through Customs with your luggage and immediately place it on the "Connecting Flights" re-check belt. If you are flying international-to-international via a major hub like Newark or Chicago, United often utilizes "ITI" (International-to-International) baggage handling, where the bags stay in the secure area, but you should always check the white tag on your bag at initial check-in to see if it lists your final city. If you have booked two separate tickets (self-transfer), you will always have to collect your bags at the layover city and check them in again for the second flight.