All cities and villages in UK
- Old Rayne
- Old Romney
- Old Sarum
- Oldshore
- Oldshore Beg
- Oldshoremore
- Old Somerby
- Old Town
- Old Walker
- Old Warden
- Old Weston
- Old Windsor
- Ollaberry
- Ollach
- Ollerton
- Olney
- Olton
- Olveston
- Omagh
- Ombersley
- Ompton
- Once Brewed
- Onecote
- Onibury
- Onich
- Onllwyn
- Onneley
- Openshaw
- Oragaig
- Orbliston
- Orbost
- Orby
- Orcheston
- Ord
- Ordie
- Ore
- Orford
- Orgreave
- Oritor
- Orlestone
- Orleton
- Orlingbury
- Ormesby
- Ormesby St Margaret
- Ormiston
- Ormskirk
- Orphir
- Orpington
- Orsett
- Orston
- Orton
- Orton on the Hill
- Orton Waterville
- Orwell
- Osborne
- Osbournby
- Osmaston
- Osmington
- Osmotherley
- Ospringe
- Ossett
- Ossington
- Oswaldkirk
- Oswaldtwistle
- Oswestry
- Otford
- Othery
- Otley
- Otley
- Otterbourne
- Otterburn
- Otterden
- Otter Ferry
- Otterford
- Otterham
- Otterhampton
- Ottershaw
- Otterton
- Ottery St. Mary
- Ottringham
- Oughtibridge
- Oulston
- Oulton
- Oulton
- Oulton
- Oundle
- Ousby
- Ousden
- Ousefleet
- Outhgill
- Out Newton
- Outwell
- Ovenden
- Over
- Over
- Overbury
- Over Compton
- Over Kellet
- Overscaig
- Overseal
- Over Silton
- Overstone
- Overstrand
- Overton
- Overton
- Overton
- Overtown
- Over Wallop
- Over Whitacre
- Over Worton
- Oving
- Oving
- Ovingdean
- Ovingham
- Ovington
- Ovington
- Ovington
- Ower
- Owermoigne
- Owmby
- Owslebury
- Owston
- Owston Ferry
- Oxborough
- Oxcombe
- Oxenhope
- Oxenwood
- Oxford
- Oxhill
- Oxnam
- Oxshott
- Oxted
- Oxton
- Oxton
- Oxton
- Oxwich
- Oykell Bridge
- Oyne
- Oystermouth
- Packington
- Packwood
- Padbury
- Paddington
- Paddlesworth
- Paddock Wood
- Padeswood
- Padgate
- Padiham
- Padside
- Padstow
- Pagham
- Paible
- Paignton
- Pailton
- Painscastle
- Painswick
- Paisley
- Pakefield
- Pakenham
- Pale
- Sea Palling
- Palmers Green
- Palnackie
- Palnure
- Pampisford
- Panbride
- Pancrasweek
- Pancross
- Pandy
- Pandy
- Panfield
- Pangbourne
- Pannal
- Pannanich
- Panshanger
- Pant
- Panteg
- Panton
- Pant-y-dwr
- Pant-y-ffynnon
- Panxworth
- Papplewick
- Papworth Everard
- Par
- Parbold
- Parham
- Parkend
- Parkeston
- Parkgate
- Park Gate
- Parkgate
- Parkham
- Parkstone
- Park Street
- Parracombe
- Partick
- Partington
- Partney
- Parton
- Parton
- Partridge Green
- Partrishow
- Parwich
- Passenham
- Paston
- Paston
- Patcham
- Patching
- Pateley Bridge
- Pathhead
- Pathhead
- Patna
- Patney
- Patricroft
- Patrington
- Patterdale
- Pattingham
- Pattishall
- Pattiswick
- Paul
- Paulerspury
- Paull
- Paulton
- Pauntley
- Pavenham
- Pawlett
- Paxton
- Payhembury
- Paythorne
- Peak Forest
- Peakirk
- Peanmeanach
- Pearsie
- Peasemore
- Peasenhall
- Peasmarsh
- Peatling Magna
- Peatling Parva
- Pebmarsh
- Pebworth
- Pedmore
- Peebles
- Pegswood
- Pelcomb Cross
- Peldon
- Pelsall
- Pelton
- Pelton Fell
- Pelynt
- Pemberton