The event takes place on Friday, 20 May on the A334 and The Square in Wickham.
The Square will be closed to traffic from 12pm on Thursday, 19 May until 10am Saturday, 21 May.
The A334 will be closed between the traffic signals at Blind Lane and the roundabout junction of the A32 from 5am to 8pm on Friday, 20 May.
Arrangements have been made for horse boxes to be parked on the east side of the A334 between the north end of the square and the junction at Blind Lane and Titchfield Lane.
Temporary parking restrictions will be introduced to maintain traffic flow on the local diversion route through Wickham. Any vehicle parked in an unauthorised place will be towed away.
Motorists not attending the fair may wish to consider alternative routes around Wickham.
A dedicated telephone number has been set up for residents and businesses in the area. They have been contacted directly about this.
Inspector John Stribley said: “Wickham Horse Fair is set to return this Friday, 20 May, and anyone planning to attend should make sure they are aware of the road closures and the parking arrangements before they start their journeys.
“Officers will be on site throughout the event to respond to any issues that may arise.
“We have been working closely with organisers, local authority partners and businesses to make sure this is a safe environment for residents and visitors during the event.”