Sorry for the confusion about domestic vs. international, folks; I was a little too wordy in my original post. My question was about stopovers on an international award itinerary, and it sounds like in most cases that means a >24hr stay.

Assuming you are wanting to stop at an appropriate hub for your carrier, does it matter whether the stopover occurs on the outbound portion of your itinerary or the inbound (i.e., return portion)?

Thanks to everyone for your responses!

no

I recall doing a NW award on CO that permitted me a stop-over at a non-hub: YEG-MSP-Cleveland s/o Cleveland-EWR-SCL.

This works well for college students on spring break. Three times I've
brought a daughter home from college 4-5 days, and then on to
Europe or Japan for 4-5 more days using the "stopover" feature of an
international frequent flyer ticket.

Stopovers vs Transfers
 

As mentioned with previously, an international transfer is < 24 hours. I found this "loophole" as cost effective in scheduling business meetings accross the US. A recent itinerary;

Tu - SFO to DEN - Depart 6:49 pm, Arrive 10:11 pm
We - DEN to DFW - Depart 6:30 pm, Arrive 9:30 pm
Th - DFW to ORD - Depart 7:15 pm, Arrive 9:38 pm
Fr - ORD to LHR - Depart 6:20 pm, Arrive 8:15 am (Saturday)
Su - LHR to IAD - Depart 4:30 pm, Arrive 7:30 pm
Mo - IAD to SFO - Depart 5:50 pm, Arrive 8:36 pm

The fare was priced as a SFO to London roundtrip (approximately $650). This was much less expensive then pricing individual, point to point fares. The other benefit, is that I was able to upgrade these flights using 2 United SWU's.

A couple of weeks ago, I booked an award ticket for an upcoming trip.

Mo - SFO to LAX
Tu - LAX to OKC
We - OKC to PHL
Th - PHL to IAD
Fr - IAD to LHR
Tu - LHR to SFO

It was not easy booking this award, as there appears to be additional restrictions (versus paid ticket). After several calls with the award center (and various explanations on why this routing is not permittable), an agent did ticket this itinerary.

The one major catch was the mileage limitation on an award ticket.

HChrist, you may be able to spend 2 days with your friends (coming and going) by transferring via their city.

Thanks. All of the responses on stopovers have opened my eyes to some interesting techniques. The <24hr transfer idea is really fascinating. It had never occurred to me that you could arrange 23-hour stops in three or four different cities on an international itinerary and have them treated as simple transfers!

I called UAL about an upcoming award flight, and I was able to arrange a 6-day stopover in DEN with no problems at all. Seems like a great option -- at least if you have friends/family in major hubs..

Anyway, thanks FT! A month ago, I wasn't even sure what a stopover *was* :)