Many ceremonies were across the UK due to the coronavirus pandemic, leaving applicants waiting for the security that citizenship provides.
Home Office figures show 90 people attended citizenship ceremonies in Aberdeenshire in 2020 – 110 fewer than the year before.
It means that since the figures were first published in 2004, 2,261 people have gained citizenship in the area.
Just under 75,000 people took part in citizenship ceremonies nationally last year, including around 1,000 at British consulates abroad.
This was a drop of 34 per cent from 2019, and the lowest annual figure since 2004.
The events are the final step in the process to full citizenship and being able to obtain a British passport, but were suspended for large parts of 2020 due to Covid-19. Participants are asked to make an oath of allegiance to the Queen and pledge to respect the rights, freedoms and laws of the UK. They are then presented with a certificate of British citizenship and a welcome pack.
A Home Office spokesman said local authorities paused in-person ceremonies to put the health of the public first, but they have now restarted.
He added: “We continue to work closely with local authorities to ensure anyone who requires a British citizenship ceremony can attend one as quickly as possible."