The group initially met in precinct caucus and then held a county convention to consider candidates for office.
County Commissioner Kenneth Maryboy, who has been a Commissioner for two terms, was defeated in convention by challengers Rebecca Benally and Roger Atcitty.
Benally and Atcitty will meet in a Democratic Party primary in June to determine who will be the party candidate in the general election in November.
The primary election is for voters in the five precincts that make up the Second District Commission district.
Maryboy is also a candidate for Navajo Nation President.
In other business at the convention, Kendall Laws secured the party nomination for San Juan County attorney. Laws defeated Walter Bird after receiving approximately 69 percent of the delegate votes.
In the Democratic Party, a candidate who secures more than 60 percent of the delegate votes avoids a primary election.
A new state law, which will go into effect after the current election, restructures how candidates are selected. While the caucus and convention system are retained under the new law, candidates can force a primary election if they secure enough petition signatures.
In addition to the contested races, three candidates for county office were unopposed and will represent the Democratic Party in the general election.
They include assessor Howard Randall, clerk Dawn Shaw, and recorder Tina Corrao.
County Clerk Norman Johnson said that primary election ballots will be sent to voters who are registered as Democrats. Since the Democratic primary is open to all registered voters, non-party members will need to request a ballot to participate in the primary election. All county elections will use mail-in ballots in 2014.