Hillary Clinton won the Northern Mariana Islands Democratic caucus on Saturday, picking up four of the territory's six delegates.
One of the Pacific archipelago's superdelegates had decided to back Clinton before the caucus.
The victory adds to Clinton's substantial delegate lead over Sanders. the candidates will face off again on Tuesday in Florida, Missouri, North Carolina, Illinois and Ohio.
The commonwealth's 52,000 residents are U.S. citizens. They can participate in the presidential nomination process, but are not permitted to vote in the general election.
The caucus on Saturday was the first-ever Democratic caucus in the Northern Mariana Islands.
The Republican caucus in the Northern Mariana Islands will occur this coming Tuesday. It is a winner-take-all contest with nine delegates.
Also on Saturday, Sen. Ted Cruz (R-Texas) picked up the support of a Republican delegate in the U.S. territory of Guam.
The Pacific island nation, home to a growing U.S. military base, does not have a traditional Republican caucus or primary. The territory's nine delegates decide which candidate to support on their own.
The executive director of Guam's Republican Party told CNN that the remaining delegates will be meeting with candidates and announcing endorsements in the next two weeks.
The Democratic primary in Guam will take place on May 7.