It is located within the Selkirk Mountains at the confluence of the Kootenay and Columbia Rivers. It is a regional trade and transportation centre, with a local economy fueled by forestry, mining and tourism. It is home to Selkirk College, a regional airport, a pulp mill, and several sawmills. The population of 7,259 people includes a large number of Doukhobors, who were largely responsible for much of Castlegar's early development and growth. A sizeable Portuguese community grew as workers, mainly from the Azores islands, moved in to take up employment in the area. The area which was to become Castlegar was an important centre for the Sinixt (Lakes) Peoples. Outside the city limits are the small surrounding communities of Ootischenia, Brilliant, Robson, Robson West, Raspberry, Tarrys, Thrums, Glade, Shoreacres, Fairview, Genelle, Pass Creek and Krestova. There are also the much smaller communities of Deer Park, Renata, and Syringa on Lower Arrow Lake. Taken together, these outlying areas comprise an approximate population of a further 8,000 people.
On September 5, 1811, David Thompson arrived at the location where Castlegar now sits, where he camped near the mouth of the Kootenay River. A plaque dedicated to David Thompson can be found on the east bank of the Columbia River overlooking the present day site of Castlegar.
The first settlement in the area was West Waterloo, now known as South Castlegar. There was widespread provincial interest in gold prospecting in the late 19th century, and by 1895 there were forty houses in Waterloo. The town boomed until the end of the century when interest in the local mines declined.
Castlegar takes its name from Castlegar, County Galway in Ireland, the ancestral home of townsite founder Edward Mahon. (Castlegar is on the eastern boundary of the city of Galway.) The city was planned in 1897. Around 1902, the Canadian Pacific Railway (CPR) built the bridge at Castlegar and laid the wide gauge railway tracks to Trail. They put in a box car station at the old Waterloo trail crossing and called it Kinnaird Station in honour of Lord Kinnaird who was a shareholder in the CPR.
There was little in Castlegar until after the completion of the CPR bridge. A Mr. Farmer built the first store in town, housing both the post office and the town hall. William Gage built the Castlegar Hotel in 1908, standing until 1982 when it was destroyed by fire. Also in 1908, the first schoolhouse was built by a few local residents who bought the lumber and erected the building. A dance pavilion, garage, tourist cabins and a slaughterhouse had all been established by 1925.
On October 30, 1946, Castlegar was incorporated into a village, then in 1966 into a town. It amalgamated with the neighbouring town of Kinnaird into a city on January 1, 1974, effectively doubling the population. On May 20, 2004, the City's boundary was extended to include the Blueberry Creek Irrigation District.
Castlegar is located in the border area between the Sinixt (Interior Salish) and the Ktunaxa Indian bands. Experts cannot agree where the Ktunaxa range ended, and where the Sinixt began. There was much overlapping of cultural and territorial activity between the two peoples. Most recent information suggests that the Sinixt were the original people in the area, and that the Kootenai arrived several hundred years ago from central Canada.
"Qepitles" was a site on the north side of the Kootenay River, just above the junction with the Columbia River. Native implements (arrowheads, pestles, etc.) have been found along the nearby Arrow Lakes. A reconstructed kekuli dwelling was formally located on Zuckerberg Island, at the confluence of the Kootenay and Columbia rivers.
The Doukhobors put a ferry into operation near Brilliant on the Kootenay River in 1910 and the Christian Community of Universal Brotherhood (CCUB) made an application to the CPR for a railway station and siding to this point. Brilliant was the centre of the CCUB commercial enterprises. Located on the site was the Brilliant Jam Factory, a grain elevator, and a flax seed mill.