Geohashing /ˈdʒiːoʊˌhæʃɪŋ/ is an outdoor recreational activity inspired by the webcomic xkcd, in which participants have to reach a random location (chosen by a computer algorithm), prove their achievement by taking a picture of a Global Positioning System (GPS) receiver or another mobile device and then tell the story of their trip online. Proof based on non-electronic navigation is also acceptable.^[1]

The geohashing community and culture is extremely tongue-in-cheek, supporting any kind of humorous behavior during the practice of geohashing and resulting in a parody of traditional outdoor activities.^[2] Navigating to a random point is sometimes done with a goal in mind. Some geohashers document new mapping features they find on the OpenStreetMap project, clean up litter, or create art to commemorate the trip, among other activities.

A variation on geocaching, known as geodashing, features a closely comparable principle, with participants racing between coordinate points.

On May 21, 2008, the 426th xkcd comic was published. Titled "Geohashing", it described a way for a computer to create an algorithm that could generate random Global Positioning System (GPS) coordinates each day based on the Dow Jones Industrial Average and the current date.^[3] The algorithm was quickly seized by the xkcd community, which used it as intended by xkcd creator Randall Munroe.^[4]

Originally a stub where people willing to try the algorithm in real life were to issue their reports, the geohashing official wiki expanded in the following weeks and was a working website as early as June 2008.^[4] The current expedition protocol was then established during the following years, with the creation of humorous awards, regional meetups and a hall of amazingness for the various geohasher achievements.^[5]

Over time, geohashing gained fame across the internet and now counts more than 15,000 expedition reports.^[6] Over a thousand users are registered on the geohashing wiki, though not all are currently active.^[7] Geohashing has spread mostly in North America, Europe and Australia, especially around cities.^[8]

Geohashing divides the earth into a grid made up of graticules which are one degree wide in latitude and longitude. Inside these graticules, a random location is set. Geohashers then have the opportunity to go at the chosen location, either inside their own graticule or in a nearby one. If the location is inaccessible or in a private area, geohashers are advised not to try to reach it, although seemingly-inaccessible locations have been reached several times. In addition to the repeating location in each graticule, each day there is a single global hashpoint, much more challenging to reach.^[9]

• Benchmarking (geolocating) – Outdoor gamePages displaying short descriptions of redirect targets
• Degree Confluence Project – Online volunteer photography project
• Letterboxing (hobby) – Outdoor hobby
• Location-based game – Game which reacts to the player's location
• Orienteering – Group of sports that requires navigational skills

• Geohashing official wiki