[4] In the 1950s and 1960s, Gilgil was used as a base for the rotation of British infantry units who, typically, would progress from the United Kingdom to the British Army of the Rhine (BAOR) in Germany, to Kenya (with detachments left en route in the nascent Gulf states) and then on to Hong Kong.
The towns population has grown considerably since 2007 as many of the internally displaced people fleeing post-election violence after the 2007 presidential election opted to settle in GilGil and Naivasha.
The community also hosts two large Kenya Defence Forces (KDF) barracks, the headquarters of Kenya Police Service's Anti-Stock Theft Unit (4 kilometres northwest of the town centre) and the National Youth Service training college (to the west of the town).
Much of the town's real estate has expanded thanks to military personnel who are routinely engaged in overseas peace-keeping missions, with the resulting monetary benefits being invested in property, both residential and commercial.
Nearby destinations include Lake Elementaita, northwest along the Nairobi-Nakuru highway, which serves as a bird sanctuary and has a number of hotels and lodges.
Dating back between 700,000 and one million years old, Kariandusi is possibly the first Acheulian site to have been found in Situ in East Africa.
A rise in the Lake level drove prehistoric men from their lakeside home and buried all the tools and weapons which they left behind in a hurry.
The Acheulian stage of the great hand-axe culture, to which this site belongs, is found over a very widespread area from England, France, and southwest Europe generally to Cape Town.
In the recent past, members of the military both active and retired personnel have invested significantly in the town's property market and also in retail business.