A total of 41 people were arrested on Saturday in an "extremely busy night" for gardai at the Donegal Rally.
One person was arrested for an alleged assault on a garda while 21 others were held for public order offences.
Another was arrested for assault, while four more were detained for dangerous driving.
Five people are also in custody for drink driving offences.
All of those arrested were brought to Letterkenny garda station between 5pm on Saturday and 7am on Sunday.
The 2019 Donegal International Rally will attract 70,000 fans over three days.
Gardai also warned all those attending the event to ensure they stay safe on the roads.
A spokesman said: "The Rally is not yet over and we would like to again take this opportunity to urge everyone to drive carefully on our roads and have regard for others on the roads also.
"We want everyone to make it home safely from the Rally.
"Let's hope the sun shines today for the final stages!”
