The second closest airport would be Hartford's Bradley International Airport (BDL).
Warwick is just under an hour's drive from Foxwoods; Bradley is just over an hour's drive.
If you wanted to avoid renting a car, you could try to connect to a Foxwoods bus. There's one bus company, Conway Tours, that leaves from the Warwick Mall in Rhode Island.
Or one that departs Union Station in Hartford, Peter Pan Bus Lines.
Both would require cab rides from the airport.
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