If you worked any of the K2BSA activations during Jamboree on the Air and are seeking to send a QSL card, you can find details on each operation at K2BSA QSL Paths. You can sort this table by call, date, etc. It typically provides the call sign of the control operator as the QSL address — and almost always asks for a Self-Addressed Stamped Envelope, SASE.
You can find addresses for any USA amateur radio call sign at QRZ.com and a few other services.
Thanks for getting on the air during JOTA and for working K2BSA.