The Merriam-Webster's Online Dictionary provides the following definitions, which seems like a good place to start:

Hash House [hásh haus] (plural hash house·es) noun (1869)

1. an inexpensive eating place

Harriers [har-E-erz] noun (1542)

1. any of a breed of hunting dogs resembling a small foxhound and orig. bred for hunting rabbit

2. a runner on a cross-country team

Basically hashing is a form of non-competitive cross-country running with the main objective of working up a decent thirst. Great emphasis is placed on the social aspects - particularly the communal boozing session at the aprés-hash. It's a fun activity and not be taken at all seriously.

ARE YOU A VIRGING?

If you have half a mind to join the Hash, that's all it takes. If you have hashed before you will know the format but for the newcomers here's a quick rundown on what happens.

The Hash generally meets at a pub chosen by the HARES and the HOUNDS set off at the appointed hour along a clearly defined trail (blobs of chalk or sawdust) with the front runners calling "ON, ON" for the benefit of the slower runners and latecomers catching up.
Every 500 metres or so the trail will end signified by a check mark which may be in the form of a line or a circle - ask the hare before you set out. The frontrunners on reaching the check start searching for the new trail.. This can start up to 50 metres from the check in any direction.
The time taken by the frontrunners to find the new trail allows the runners at the back (the "social or chat-pack") to catch up thus increasing the chances of everyone reaching the the pub at the end at roughly the same time. The frontrunners will usually find that the cunning hares have laid some FALSE TRAILs in addition to the the real trail - these falsies usually consist of up to 3 blobs followed by an X or a T (again ask!).
This ensures that the really fit types, known as FRBs (Front Running Bastards) will become exhausted more quickly and be forced to join the social pack. Another device used by Hares to achieve the same objective is the LOOP whereby the trail might go round 3 sides of a field allowing the back markers to run across the fourth.
Hash runs are usually 4 - 7 miles long and are designed to last 1 - 1½ hours. Revelries in the pub after the run are up to the individual but it has been known for some muddy sweaty hashers to be turned out of the pub at closing time...

ORGANIZATION

The Hash House Harriers is a decentralized organization with each chapter (sometimes called a Kennel) individually managed with no uniting organizational hierarchy (although the locations of national and international gatherings are decided by a meeting involving representatives from a number of hashes). A kennel's management is typically known as the MisManagement and consists of individuals with various duties and titles. There are more than 1,700 kennels spanning all seven continents. Most major cities are home to at least one chapter. Kennels typically contain 20-100 members, usually mixed-sex and some metropolitan area Hashes can draw more than 1,000 hashers to an event.

A BRIEF STORY

To begin at the beginning, as they say in all the best yarns, one should go back to 1938 in Kuala Lumpur in what is now Malaysia when a group of ex-patriates associated with the rubber plantations started a modified paper chase in order to work up a decent thirst before retiring to the Selangor Club. There the restaurant was known locally as the "Hash House" so naturally the name was adopted by the harriers and in contrast to other groups undertaking similar activities the name stuck. The particular genius of the founding father, A S Gispert, nicknamed "G", was to make the traditional hare & hounds running more fun by making it non-competitive. But you knew all that really, didn't you?

The Original Hash House (Kuala Lumpur) Circa 1938

So we will move on quickly to the Second World War and its aftermath which became known as the Malayan Emergency when British and Australian troops joined in the fun and when posted elsewhere began new chapters and the Hash House Harriers spread throughout the world rather like the AIDS virus spread from a central origin in Africa. You knew that, too? Well, perhaps not the fact th at Hashing is an affliction akin to AIDS but how's this for exponential growth:

• 1938 Kuala Lumpur H3 (Mother Hash) founded
• 1947 Royal Bordighera H3 founded - first known offshoot, ceased early 1960s
• 1962 Singapore H3 founded
• 1967 Dhekelia H3 - second hash in Europe, after RBH3 above.
• 1967 Sydney H3 - first Hash in Australia
• 1971 Fort Eustis H3 - first Hash in the North America
• 1969 Commando Forces H3 founded - first Hash in UK
• 1971 Westcombe Park H3 founded - oldest monthly running Hash in UK
• 1973 KL H3 1500th run - 35 other Hashes "known" to exist
• 1974 Bicester H3 founded - oldest weekly running Hash in UK
• 1975 Surrey H3 founded
• 1976 London H3 founded
• 1977 90 Hashes known in 35 countries
• 1984 Harrier International founded
• 1986 555 Hashes known in 85 countries
• 1988 700 Hashes known in 125 countries
• 2000 1570 Active Hashes known in 184 countries with 200,000 hashers

Both servicemen and diplomats have been largely responsible for the contagion spreading and indeed the first known recorded hash in the UK was the Commando Forces H3 based at Plymouth founded in 1969 by the then Col Ray Thornton (ex-JM of Singapore H3) which flourished in the early seventies but like many military hashes petered out when postings decimated the membership Ray went on to found Bicester, Donnington and Looe & Liskeard which survived by becoming predominantly civilian hashes.

Click here for more historical background.

HASH HINTS

Here are a few suggestions and explanations which may help a newcomer to enjoy the Hash but first and foremost please bear in mind that hashing is supposed to be fun and don't ever take it seriously: