What is the longest UA MR out of SEA you can think of?

SEA-ORD-MIA and back?

sea-pdx-lax-iad-sju-iad-lax-sea is a decent one, or if you want to nest two tix you could try. 1 sea-pdx-lax-iad-sju-iad-mco (stopover) 2. mco-lax-nrt-sin-nrt-sfo-mco. 1. mco-iad-sfo-pdx-sea. Tally up the miles on that one. :)

Giggy's are good. If you're looking for domestic runs, heading to Boston via SFO makes for a long trip. In general, leaving the west coast from SFO will get you the most miles (as opposed to LAX, SEA, PDX, etc.). Aside from BOS (2704), PHL (2521) will net you a bit more than IAD (2419) out of SFO.

I'm assuming you mean MR in the continental US. Although certainly not the longest, SEA-SFO-BOS-SFO-SEA is pretty painless and yields many miles. With one more connection each way you could do SEA-SFO-IAD-MIA and back for over 8K miles (compare that to your proposed SEA-ORD-MIA which is only 5836 miles). IMO, adding extra connections only yields marginal improvements in total mileage.

Thanks to all who replied. Yes, I meant in the continental U.S. but while we're at it, what's the longest intl MR anyone can think of from SEA (with a preference for optimization in terms of miles relative to number of legs/time traveled)?