Each Commoner is located in a County (tracked in the GNDT, and defaulting to Dorset), an entry from the list below, which also lists the Counties which neighbour which other Counties:
Bedfordshire: Buckinghamshire, Cambridgeshire, Hertfordshire, Huntingdonshire, Northamptonshire
Berkshire: Buckinghamshire, Hampshire, Oxfordshire, Surrey, Wiltshire
Buckinghamshire: Bedfordshire, Berkshire, Hertfordshire, Middlesex, Northamptonshire, Oxfordshire
Cambridgeshire: Bedfordshire, Essex, Hertfordshire, Huntingdonshire, Lincolnshire, Norfolk, Northamptonshire, Suffolk
Cheshire: Derbyshire, Lancashire, Shropshire, Staffordshire, Yorkshire
Cornwall: Devon
Cumberland: County Durham, Lancashire, Northumberland, Westmorland
Derbyshire: Cheshire, Leicestershire, Nottinghamshire, Staffordshire, Yorkshire
Devon: Cornwall, Dorset, Somerset
Dorset: Devon, Hampshire, Somerset, Wiltshire
County Durham: Cumberland, Northumberland, Yorkshire
Essex: Cambridgeshire, Hertfordshire, Kent, Middlesex, Suffolk
Gloucestershire: Herefordshire, Oxfordshire, Somerset, Warwickshire, Wiltshire, Worcestershire
Hampshire: Berkshire, Dorset, Surrey, Sussex, Wiltshire
Herefordshire: Gloucestershire, Shropshire, Worcestershire
Hertfordshire: Bedfordshire, Buckinghamshire, Cambridgeshire, Essex, Middlesex
Huntingdonshire: Bedfordshire, Cambridgeshire, Northamptonshire
Kent: Essex, Surrey, Sussex
Lancashire: Cheshire, Cumberland, Westmorland, Yorkshire
Leicestershire: Derbyshire, Lincolnshire, Northamptonshire, Nottinghamshire, Rutland, Warwickshire
Lincolnshire: Cambridgeshire, Leicestershire, Norfolk, Northamptonshire, Nottinghamshire, Rutland, Yorkshire
Middlesex: Buckinghamshire, Essex, Hertfordshire, Surrey
Norfolk: Cambridgeshire, Lincolnshire, Suffolk
Northamptonshire: Bedfordshire, Buckinghamshire, Cambridgeshire, Huntingdonshire, Leicestershire, Lincolnshire, Oxfordshire, Rutland, Warwickshire
Northumberland: Cumberland, County Durham
Nottinghamshire: Derbyshire, Leicestershire, Lincolnshire, Yorkshire
Oxfordshire: Berkshire, Buckinghamshire, Gloucestershire, Northamptonshire, Warwickshire
Rutland: Leicestershire, Lincolnshire, Northamptonshire
Shropshire: Cheshire, Herefordshire, Staffordshire, Worcestershire
Somerset: Devon, Dorset, Gloucestershire, Wiltshire
Staffordshire: Cheshire, Derbyshire, Shropshire, Warwickshire, Worcestershire
Suffolk: Cambridgeshire, Essex, Norfolk
Surrey: Berkshire, Hampshire, Kent, Middlesex, Sussex
Sussex: Hampshire, Kent, Surrey
Warwickshire: Gloucestershire, Leicestershire, Northamptonshire, Oxfordshire, Staffordshire, Worcestershire
Westmorland: Cumberland, Lancashire, Yorkshire
Wiltshire: Berkshire, Dorset, Gloucestershire, Hampshire, Somerset
Worcestershire: Gloucestershire, Herefordshire, Shropshire, Staffordshire, Warwickshire
Yorkshire: Cheshire, Derbyshire, County Durham, Lancashire, Lincolnshire, Nottinghamshire, Westmorland