100 Mile House was originally known as Bridge Creek House, named after the creek running through the area. Its origins as a settlement go back to the time when Thomas Miller owned a collection of ramshackle buildings serving the traffic of the gold rush as a resting point for travellers moving between Kamloops and Fort Alexandria, which was north of 100 Mile House farther along the HBC Brigade Trail. It acquired its current name during the Cariboo Gold Rush where a roadhouse was constructed in 1862 at the mark up the Old Cariboo Road from Lillooet. In 1930, Lord Martin Cecil left England to come to 100 Mile House and manage the estate owned by his father, the 5th Marquess of Exeter. The estate's train stop on the Pacific Great Eastern railway is to the west of town and called Exeter. The town, which at the time consisted of the roadhouse, a general store, a post office, telegraph office and a power plant, had a population of 12. The original road house burned down in 1937. 100 Mile House residents often go by the demonyms "Hundred Milers, Huncity" 100 Mile House is on Secwepemcunceded territory. The nearest Secwepemc band is the Tsq'escen, for whom a geographic reference point is the Canim Lake Reserve.
100 Mile House is a centre for outdoor activities and is becoming increasingly known for its richness of bird life. The surrounding area features hundreds of lakes for boating and fishing including 101 Mile Lake, 103 Mile Lake, Lac La Hache, Canim Lake, Horse Lake, Green Lake, Bridge Lake and Sheridan Lake. The Cariboo ski marathon attracts a large and international field of cross-country skiers. The surrounding communities have various activities for residents and visiting tourists, including rodeos and an extensive trail system. This area is known for outdoor activities including hiking, snowmobiling, cross country skiing, and ATV riding. There are government campgrounds at Green Lake, Bridge Lake and Lac La Hache. There are also many private campsites around the area that also offer cabin and fishing boat rentals and RV hook-ups.
100 Mile House has a humid continental climate with mild summers combined with cool nights, along with cold, but not very cold winters for its latitude. In spite of the moderation that comes from its relative proximity to the Pacific Ocean, extreme winter temperatures can occasionally occur, with a record low of. 100 Mile House is located in a rain shadow of the coastal mountains, resulting in reduced precipitation, much of it falling as snow.
