After starting eighth on the grid, Rea led by lap three following a stunning couple of opening circuits as he moved ahead of Kawasaki team-mate Tom Sykes.
Northern Irishman Rea was 2.88 seconds clear of England's Sykes at the finish with Welshman Chaz Davies in third.
The success was defending champion Rea's ninth win of the season.
Despite being eighth and seventh on the grid, Kawasaki rider Rea and Sykes were able to produce pace which none of the other competitors could live with.
Rea's ride maintained his sequence of podium finishes at the American venue going back to 2014 as he extended his championship lead over Sykes.
The championship now takes a five-week break until the next round in Germany and Rea said he was "going to enjoy the flight home now".
"What a way to go into the summer break and what a day for Kawasaki. A one-two again," added Rea, 30.
Davies, who finished 4.847 seconds behind Rea in Sunday's race, is 115 points adrift of Rea - champion for each of the last two years - with Marco Melandri a further 37 points back.
The winner's fellow Northern Irishman Eugene Laverty earned a creditable sixth place on his Milwaukee Aprilia after crashing out of Saturday's race one, while England's Alex Lowes finished in ninth spot.
Ducati rider Davies won race one on Saturday in front of Rea and Sykes.
Jonathan Rea extended his lead at the top of the World Superbike standings to 59 points after dominating race two at Laguna Seca in California.