United and Air Canada have round-trip flights from Denver (DEN) to Hong Kong (HKG) for $538-$663. Flights January, February, March, April, May, August, September, October, and November. No weekend departures. No Thanksgiving dates.
Air Canada fares are cheaper, but have two connections on the return. United fares have one connection each-way, but are more expensive.
Some small OTAs on Skyscanner have this for as low as $538; which is cheaper than the airline.
Click for more details and booking links Cheap Flights: Denver to Hong Kong $538-$663 round-trip (No Thanksgiving) [Jan-May, Aug-Nov]- United / Air Canada