Northern Ireland council elections use the Single Transferable Vote (STV) system, which is also used for Stormont Assembly elections.
It is a method of proportional representation to help ensure a range of voices and minorities have a chance of being among those elected.
Voters rank candidates in order of their preference and this is used to elect several councillors to each local district rather than just one.
Read more: Northern Ireland council election: Key battlegrounds as parties compete for votes
Councils in Northern Ireland have five, six and seven-seat district electoral areas (DEAs).
On the ballot paper, voters mark a 1 beside their favourite candidate, 2 beside their second favourite and so on for as many candidates as they wish.
How are the votes counted?
Each candidate seeks to achieve a minimum number of votes to be elected.
This number is called a quota. It is calculated based on the number of seats available in the district electoral area and the number of people who have voted.
The first-preference votes for each candidate (those who have a 1 marked beside their name) are added up and any candidate who has achieved this quota is elected.
If a candidate has more votes than needed to reach the quota, their extra or surplus votes are transferred to the remaining candidates. So the second-preference candidate (marked 2 on these ballot papers) receives those votes instead.
If candidates do not meet the quota, the candidate with the fewest votes is eliminated and their second-preference votes are transferred to the remaining candidates.
The process continues round by round with the lowest candidate knocked out and their votes being transferred to the others.
Eventually more seats are filled as candidates remaining in the race reach the quota.
If there are no more votes to distribute and a seat remains unfilled, then the remaining candidate closest to the quota is deemed elected.
When will the results of the election be announced?
Counting of the votes begins on Friday morning, the day after the election.
However, it could take two days of counting or more before the final results are known.
Make sure to check out our full coverage of the election as the count unfolds for up-to-date results, reaction and analysis.
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