The largest policing event in Thames Valley's history is expected to take place in Windsor on Monday, the police and crime commissioner has said.
The Queen's funeral at Westminster Abbey will be followed by a committal service at Windsor Castle.
PCC Matthew Barber said he believed there would be a bigger crowd than the 150,000 at the Royal Wedding of Prince Harry and Meghan Markle in 2018.
Queen Elizabeth II died at Balmoral on Thursday, aged 96.
Mr Barber described Windsor as a "pretty small town" which "presents its own challenges".
"It will be undoubtedly the largest policing operation in Thames Valley's history and it's really important that we do that to keep the public safe," he said.
The force has deployed its armed response, mounted section and drone units as part of its security preparations, while specialist officers will patrol the busy waterways.
Officers have also been patrolling areas of the town with dogs, including the centre, the Long Walk, and Home Park, searching phone boxes, drains, and bins for suspicious items.
Thames Valley Police said it was to "protect local residents, business and visitors whilst the town is exceptionally busy".
Mr Barber said normal staff numbers were being boosted, as the force would have to juggle its response with day-to-day policing responsibilities.
He added: "There's lots of pressure on officers, and people who might have wanted extra leave have been told they need to put that off for the period.
"All of the police officers and staff I've spoken to are really pulling out the stops.
"There are a lot of people doing overtime, doing extra duties, but they're proud to play their part in this significant national event."
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Watch: Timelapse of flower tributes growing outside Windsor Castle
Mr Barber said it had been a "very emotional" time for officers who "swore their oath of allegiance to Her Majesty", many of whom "served the Queen very closely on duties at Windsor and when she's been out and about".
He said visitors on Monday should expect traffic congestion and use public transport where possible.
Following the state funeral the Queen's coffin will travel to Windsor and be taken by state hearse to St George's Chapel at Windsor Castle via the Long Walk.
A televised committal service for Her Majesty will then take place.
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