Greater Manchester Police billed United £625,236 for policing games last season, according to data released to the M.E.N. via Freedom of Information requests.
That's more than any other club in Britain paid for policing.
City were billed £595,822 - the second highest total in the country.
London-based Premier League and EFL clubs, meanwhile, were charged a combined total of just £478,808.
Crystal Palace paid just £7,429 of that, while West Ham paid as little as £41,973 and Arsenal £55,490.
Liverpool paid the next most after City and United, with a total policing bill of £590,739.
Leeds United (£459,798), Everton (£405,778) and Rangers (£306,770) were next.
The Manchester Derby at the Etihad was the most expensive league game of the season, costing City £58,912.90.
Fans of the Swiss side were accompanied during an organised march all the way from the top of Chapel Street, through Salford and to Old Trafford in November last year.
Rolling road blocks and closures were put in place for both, with transport bosses advising members of the public who work in the city centre to either go home earlier, or consider working from home if able to.
GMP say decisions on how many officers are needed at a game are decided on the level of "threat, harm and risk posed to the public" and are agreed with clubs beforehand.
Under current rules, clubs are only obliged to pay for policing in the stadium and on their land, leading to the taxpayer having to pick up large chunks of the bill for some clubs.
Muddying that though is the fact that clubs will also be paying tax as well.
Some police forces have yet to respond to the Freedom of Information requests, so the data is missing for 22 clubs from the top four divisions of English football, such as Brighton and Hull.
A total of £9.9m was paid by clubs to the forces that did respond to the requests, however.
Superintendent Julie Ellison, from GMP’s Specialist Operations, said: “The allocation of police resources for all events is based on assessments around the threat, harm and risk posed to the public.
“The resourcing levels for all football fixtures in Greater Manchester are agreed with the club prior to each match, as it is at their request that we provide policing to the stadiums.
"Clubs are charged at the appropriate rate and only pay for those resources deployed in and around the stadium footprint, which is in line with national guidelines.
“There are a number of key factors that we take into consideration which contribute to the cost of matches.
"These include the number of away fans attending, previous behaviour of home and away fans and the likely impact on communities as well as the history and rivalry between teams.
"We also use any intelligence available to us that may affect the cost of policing any given fixture.
“We will continue to work closely with all clubs across Greater Manchester, to ensure that everyone who attends matches can do so in a safe and enjoyable environment.”
Top 20 clubs and the amount charged
- Manchester United - £625,236
- Manchester City - £595,822
- Liverpool - £590,739
- Leeds United - £459,798
- Everton - £405,778
- Rangers - £306,770
- Sunderland - £288,419
- Birmingham City - £269,248
- Aston Villa - £267,415
- Wolverhampton Wanderers - £264,607
- Leicester City - £258,858
- Bournemouth - £239,582
- Celtic - £227,361
- Sheffield Wednesday - £217,286
- Sheffield United - £216,566
- West Bromwich Albion - £213,906
- Wembley - £203,389
- Derby County - £200,748
- Huddersfield Town - £187,435
- Newcastle United - £180,636