Although we all know what a hill is, it is a difficult term to define precisely. How high does a piece of ground need to be to be classed as a hill? How high does it need to be relative to the surrounding terrain? What is the difference between a summit which is the top of a hill, and one which is only a subsidiary top of another hill?

Because there is no universally agreed definition of a hill, there is a number of lists of hills in England and Wales.

There are four main ways in which hills can be defined:

• By relative height. There are three main lists within England & Wales which use relative height as the single defining characteristic of a hill:
  • Marilyns. These are hills with a drop of at least 150m on all sides. Marilyns were named as a tongue-in-cheek response to the Scottish Munros. Hills which nearly make this definition, ie have a minimum drop of 140-150m on all sides, are known as sub-Marilyns.
  • HuMPs. HuMP stands for Hundred Metre Prominence. These hills have a drop of at least 100m on all sides. Hills with a drop of 90-100m on all sides are known as sub-HuMPs
• By relative and absolute height. There are many lists that use a combination of relative and absolute height to define a hill. Some of the most common lists are:
  • Hewitts. HEWITT stands for Hill in England, Wales or Ireland over Two Thousand feet high. They require a drop of 30m on all sides (an untidy mixture of imperial and metric units!). A hill which meets the height requirement for a Hewitt, but only has a drop of 20-30m on all sides, is known as a sub-Hewitt.
  • Sims. SiMS stands for Six Hundred Metre Summits. They also require a 30m drop on all sides, and are thus similar to the Hewitts. There are slightly more Sims, as 600m is approximately 1,968 feet.
  • Deweys. Deweys are hills between 500m and 610m (2000 feet) in altitude, with at least 30m drop on all sides. They are named after the compiler of the list, Michael Dewey. A hill which meets the height requirement of a Dewey, but only has a drop of 20-30m on all sides, is known as a sub-Dewey.
  • Nuttalls. These are hills that are at least 2000 feet high with a drop of at least 50 feet on all sides. They are named after the compilers of the list, John and Anne Nuttall.
• By subjective authority. There are some lists of hills which are a subjective list by an individual or organisation, and which may have little regard for height or prominence. To be remembered, such a list needs to be compiled by an individual or organisation perceived to have some authority in hill-walking circles. Unlike the lists above, which may change as hills are more accurately measured, the lists in this section do not change over time . The three most popular lists of this type are:
  • Wainwrights. The list of 214 hills that were each given a chapter in his Pictorial Guide to the Lakeland Fells is probably the most famous hill list in England and Wales. A subsidiary list is Wainwright’s Outlying Fells, a list of smaller hills surroundng the main Lakeland range.
  • Birketts. This is a list of 541 lakeland hills over 1000 feet high, as listed in Bill Birkett’s book Complete Lakeland Fells.
  • Trail 100. In April, 2007, Trail magazine compiled a list of 100 hills, of varying heights and spread through the UK, which it suggested were worthwhile hills to climb.
• County lists. Some peak-baggers enjoy the challenge of reaching the highest point of every county in England or Wales. Such tops may be insignificant, and may not even be an obvious summit; however, such lists have the advantage of encouraging visits to every part of the country. The three most popular lists are given below. Lists of current county or unitary tops may be subject to periodic changes in local government administration. Historic counties are more stable, although there have been numerous boundary changes in the past, particularly over the last two centuries, and not all the tops are undisputed.
  • Current Ceremonial County Tops. There are 48 ceremonial counties in England. In Wales, where they are known as Preserved Counties, there are eight.
  • Current County and Unitary Authority Tops. This is a larger number of tops, many of which are in low-lying and urban areas.
  • Historic County Tops. These are the tops of the traditional 39 English Counties and 13 Welsh counties.

Other lists

There are numerous other hill lists, in addition to those the above. TUMPs are hills with Thirty and Upward Metre Prominence. These are hills with a drop of at least 30m on all sides, regardless of absolute height. There are several thousand such hills in England and Wales. All TUMPs above 500m in height are included in other lists, while many of the lower TUMPs are relatively insignificant. This is why they have not been included on this site.

Various authors have created lists of hills that take into account both absolute and relative height. These are all variations on a theme, so only the most common lists of this type have been included on this site.

Lists of favourite hills, without regard to height or prominence, are also common. Most such lists have little to commend them, but some, such as the Hardys, have merit. The list of Hardys, published in the early 1990s by Ian Hardy, aims to include the highest hill in every hill range, on every island, and in every higher administrative tier, in Britain. However, all the worthwhile Hardy hills are included in other lists, and the Hardys list is not in common use today.

There are several lists on the theme of county divisions which have not been included here. Some relate to county divisions which existed only for a relatively short period of time (eg Avon, Cleveland). These have little meaning today, and will have even less meaning in the future. Others, such as the list of the highest points of all 32 London boroughs, seem rather pedantic and have little to do with hill-walking. These types of list have been excluded.