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.

John Fleming, of Anstruther-based ICS Fisheries Ltd, stole nearly £500,000 during the six-year scam.
He reclaimed VAT on expenses his business had never incurred.
Fleming, 59, from Balmullo, pleaded guilty on indictment to a charge under the Value Added Tax Act committed between May 2007 and July 2013.
His lawyer said he had managed to pay back the cash in full by selling property he owned, but a sheriff said the scam was too serious for him to avoid jail.
Fiscal depute Eilidh Robertson told Dundee Sheriff Court: "The business owned by the accused is involved in the sale of fish, which is zero-rated for VAT.
"As a result, the accused is lawfully entitled to claim back any VAT incurred by him in the expenses involved in the sale of this fish.
"All invoices showed exorbitant levels of haulage costs being claimed by him against his alleged purchase of huge quantities of fish.
"The accused's computer was later analysed and it was uncovered that these false invoices had in fact been created by the accused on it before he had submitted them on to his accountants and induced them to make the false claim on his behalf."
Defence solicitor David Bell said: "It appears the haulage company were not charging VAT and he was assuming it was included and was claiming it back.
"He then realised they were not adding VAT and he spotted the loophole and then exploited it over a lengthy period.
"He employs six people in the business and fears it will fold without him as he is heavily involved."
Sheriff Alastair Carmichael jailed Fleming saying: "This was a fraud carried out by you on public funds, so it was a fraud on the whole community."

With temperatures at Indian Wells in excess of 105 degrees, Evans broke in the opening game but world number five Nishikori hit back immediately and captured the set in 42 minutes.
Breaks were traded again at the start of the second before Nishikori sealed the match in an hour and 24 minutes.
Kyle Edmund is also out, 6-4 7-6 (7-5) to defending champion Novak Djokovic.
Following the surprise defeat of world number one Andy Murray at the hands of qualifier Vasek Pospisil the previous evening, Evans, 26, produced a spirited performance, but some pinpoint accuracy from Nishikori saw him break again in game eight of the first set.
World number 41 Evans, who beat Dustin Brown in the previous round, continued to frequently match the quality of his Japanese opponent's groundstrokes but gradually faded as the assured Nishikori moved through to face Gilles Muller of Luxembourg in round three.
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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.
[NEXT_CONCEPT]
A Fife fisheries boss who faked invoices to scam "astronomical" sums from the taxman has been jailed for two years and eight months.
[NEXT_CONCEPT]
British number two Dan Evans was beaten 6-3 6-4 by Japan's Kei Nishikori in the second round of the BNP Paribas Open.