Are there nonstop flights from Chicago (ORD) to Porto (OPO)?

No. The fastest connection is via Toronto, about 8h 27m of total flying time.

What is the fastest connection from Chicago (ORD) to Porto (OPO)?

via Toronto ≈ 8h 27m, via Montréal ≈ 8h 28m, via Boston ≈ 8h 34m (estimated flying time, excluding layovers).

from 27,500 ANA miles, from 37,000 JAL miles (economy, one way, based on the published award charts).

Chicago O'Hare International Airport (ORD) to Francisco de Sá Carneiro Airport (OPO)・6,332 km

No nonstop flights. The fastest connection is via Toronto (YYZ), about 8h 27m of flying time (layover not included).

With milesANA 27,500 miles+ (via YUL)JAL 37,000 miles+ (via MAD)Economy, one way, estimate. Tap a connection for miles by cabin.

None.

27 one-stop options, sorted by estimated flying time. Tap one to see the airlines on each leg and booking links.

Times are estimated from distance. Check schedules, frequency and availability with the airline or a booking site.