First USA spot on 10m WSPR today was at 1312z by WG2Z (5600km). Last spot (as of 1736z) was by KE6BID (5295km) at 1720z but there could yet be later spots from the USA.
UPDATE 2020z: KE6BID did turn out to be the last USA spot.
UPDATE 2035z: Went QRT on 10m WSPR at 2030z. Still on 6m WSPR TX 20% and RX 80%.