Archaeological evidence suggests humans have been either travelling through, or temporarily residing in, the area for about 10,000 years. Pictographs found in the hot spring caves indicate that it was the Ktunaxa people who first made more permanent use of the area, particularly the hot springs, several hundred years ago.

European fur traders and trappers passed through, as did George Simpson in 1841, through what would later be named Simpson Pass, during his circumnavigation of the world. Likewise, James Sinclair led Red River colonists westward and Pierre-Jean De Smet traveled eastward, through the area. The Palliser expedition used the Vermilion Pass in 1858 and reported to British government its potential as a transportation route.

On the Columbia River side, an early homesteader included the hot spring that would later become Radium Hot Springs in his land claim in the 1880s, but it was Roland Stuart and his business partner H.A. Pearse who were successful in acquiring the 160 acres around the springs in 1890 as a provincial crown grant. While they intended on bottling the spring water, its remote location prevented such development and Stuart offered to sell the property in 1909 to the Canadian Pacific Railway Company for $3000. Though the offer was not accepted, railway engineer Robert Randolph Bruce recognized the potential for a road through the area and advocated for it in 1910 with CPR president Thomas Shaughnessy and Premier Richard McBride, as a commercial link for the province to Calgary and eastern Canada. The federal government agreed to build a road from Banff to the park boundary at the provincial border at the Vermilion Pass, while the provincial government, with some funds from the CPR, would build a road from Windermere to the border. However, the BC government under-estimated its cost, found itself over-budget and its work was suspended in 1913, while the federal government completed their portion in November 1914.

To get the British Columbia section completed, Bruce travelled to Ottawa to pitch the idea that they designate the western end of the route, through the Rockies Mountains, a national park so that road could be funded as a park improvement. With the popularity of Banff National Park made the Commissioner of the Parks Branch, James Bernard Harkin, and officials of the Minister of Interior were receptive to expanding the park system there. In May 1916 Minister William James Roche began negotiations, and the subsequent Minister of the Interior agreed with the provincial counterparts to the Banff-Windermere Agreement, that the federal government would complete the road within 4 years of the end of war, and maintain it thereafter, in exchange for the agreed upon land to be used for park purposes and a resolution to jurisdictional matters in the other federal parks in BC. The agreement was signed on March 12, 1919, and the federal government took ownership of the land in July 1919. By Order in Council 1920-0827 on April 21, 1920, the Kootenay National Park was created. The federal government repaired the provincial portion and completed the remainder, completed for public opening by June 1923.

While the Vermillion River is completely contained within the park, the Kootenay River has its headwaters just outside the park boundary, flowing through the park into the Rocky Mountain Trench, eventually joining the Columbia River. It ranges in elevation from 918 m (3,012 ft) at the southwestern park entrance, to 3,424 m (11,234 ft) at Deltaform Mountain.

The park is centred on the 94 km stretch of the Highway 93, from Radium Hot Springs to the provincial border at the Vermillion Pass. The park's size and shape are the result of the federal-provincial agreement to get the road constructed. Consequently, despite the northwest-southeast trending range and valley systems, the park cuts through several mountain ranges and river valleys.

The park's southwestern entrance, near Radium Hot Springs and the Sinclair Canyon, is the only part of the park within Southern Rocky Mountain Trench. As the highway follows Sinclair Creek, which drains westward towards the Columbia River, the park enters the Kootenay Ranges, which include Mount Berland and the western and southern faces of Mount Kindersley of the Brisco Range and Redstreak Mountain and Mount Sinclair of the Stanford Range. The eastern side of Mount Sinclair faces the valley of the Kootenay River; that and the remainder of the park drains to the Kootenay River which does eventually empty into the Columbia River but not until well outside the park and crossing the American-Canadian border twice. The park then covers a ~27 km stretch of the Kootenay River valley including the flanking mountain faces of Mount Kindersley and the Mitchell Range and Vermillion Range of the western portion of the Park Ranges. At the bridge over Kootenay River, the road and park divert northward to follow the Vermillion River upstream through the pass between Mount Wardle of the Vermillion Range and Spar Mountain of the Mitchell Range. As the park bends northward here, it expands to include more of the Kootenay River valley, including Dolly Varden Creek, Lost Creek, and Whitetail Creek. With the Mount Assiniboine Park just over the mountains to the southeast, the road and park divert northwestward again once into the valley of the Vermillion River, near where it converges with the Simpson River. After this, the park consists of the remainder of the Vermillion River drainage basin, with the Banff National Park at the Continental Divide to the north at the Ball Range and the Bow Range, the Yoho National Park to the northwest, and the peaks of the Vermillion Range to the southwest. A small portion of the Ottertail River, which drains into the Yoho National Park, is also included the northwestern end of the park, though the remainder of that border is the dividing line between the Vermillion River and the Kicking Horse River

There are only a few, small lakes in the park, most of which occur in the Vermillion River drainage basin and occur at high altitude in cirques or hanging valleys, which is typical for the Main Ranges. The Floe, Kaufmann and Talc lakes occur here, while the Dog, Olive and Cobb lakes occur in the Kootenay River basin and have more pond-like characteristics such as shallow depth and slower flow.

The Montane Spruce biogeoclimatic zone of the park's lower elevations contain forests of mostly Douglas fir, lodgepole pine, western larch, trembling poplar, and western redcedar. The shrub layer mostly include soapberry, kinnikinnick, western showy aster, dwarf bilberry, twinflower, pinegrass, Canadian bunchberry, littleleaf huckleberry, Rocky Mountain maple, alder, mountain huckleberry, oval-leaf blueberry, meadow horsetail, Devil's club, as well as common and rocky mountain juniper.

In the higher subalpine elevations, the Engelmann Spruce-Subalpine Fir biogeoclimatic zone takes over with its dominant tree species of Engelmann spruce, white spruce, subalpine fir and subalpine larch, begin to take over at higher elevations. Heathers, arctic willow, cinquefoils, moss campion, and mountain avens are the dominant vegetation in the alpine areas.

Forest fires that affected the park, exemplified by the large fires of 1968 and 2017 and the very large fire of 2003 in the Vermillion area, feature pioneering vegetation like fireweed and lodgepole pine.

An emerging drier climate, and forest fires, are resulting in the Interior Douglas-fir biogeoclimatic zone expanding into the park, with its more dominant Douglas fir, ponderosa pine and rocky mountain juniper tree stands.

A wildlife survey found 242 species of mammals, birds, amphibians and reptiles.

The largest species are the ungulates, such as the bighorn sheep, mountain goat, moose, red deer, white-tailed deer, mule deer, though there are also black bears and grizzly bears that also live in the park. Coyotes and martens are the only widespread and common carnivores in the park, though bobcats and cougars live in the southern regions. Timber wolves, lynxes, wolverines, minks, fishers, badgers, river otters, skunks and long and short-tailed weasels have also been identified but are not common. The most common non-carnivorous mammal species living in the park are the snowshoe hare, red-backed vole, deer mouse, red squirrel and Columbian ground squirrel.

Most bird species only use the park as their summer grounds or part of their migration route; only 32 species live solely in the park. Some of the most common birds include the boreal owl, yellow-rumped warbler, golden-crowned kinglet, common yellowthroat, American robin, spotted sandpiper, chipping sparrow, two-barred crossbill, rufous hummingbird, water pipit. Other bird species that may be observed include the common loon, grey and Steller's jays, Canada and snow geese, Trumpeter and Tundra swans.

The three reptiles identified were the rubber boa, common garter snake and western terrestrial garter snake.

The park experiences a continental macroclimate which is characterized by brief, cool summers and long snowy winters, but is generally drier than the areas to the west due to the Kootenay Ranges capturing moisture. Similarly, the park's mountain ranges intercept moisture that would otherwise fall on the other side of the Continental Divide, making the Banff National Park drier. Combined with the Continental Divide protecting it from the brunt of the arctic air flow, the park experiences a more mild climate than Banff.

• Park website
• 50.61957-116.069331 Radium Hot Springs Visitor Centre, 7556 Main St E. Daily 9 AM-5PM, open until 7PM on Fridays in the summer. Located in Radium Hot Springs. Also serves as the visitor centre for Kootenay National Park. (updated Apr 2023)

Contact the park office:

• Mid-May to mid-October ☏ +1 250-347-9505 or email kootenay.info@pc.gc.ca.
• Year-round toll-free ☏ +1-888-773-8888 or email information@pc.gc.ca.

Highway 93 South (also called the Banff-Windermere Highway) runs 94 km through the centre of the park. It is the only major route and can be accessed from Banff National Park to the east and Radium Hot Springs to the west. Vehicle rentals are available in Invermere, B.C. as well as in Banff and Lake Louise, Alberta.

Vancouver and Calgary have regular bus service to the nearby towns of Golden, BC and Banff, AB. There is no public transportation in Kootenay National Park. Most people travel in a personal vehicle inside the park.

Calgary and Vancouver are the closest airports serviced by major national and international carriers. Connections may be made to Cranbrook, 145 km south of Radium Hot Springs, B.C. Airport shuttles from Calgary, Alberta are available to Lake Louise and Banff near the park's east entrance.

• 50.634675-116.0390651 Radium Hot Springs, 5420 Hwy 93 (just north of Radium in Sinclair Canyon at the entrance of Kootenay National Park), ☏ +1 250-347-9485. Development of the hot springs began in earnest after a British medical journal suggested, and a 1914 chemical analysis by McGill University confirmed, the presence of radium within the water. (updated Apr 2023)

The Rockwall trail is a multi-day hike along the limestone cliff eastern escarpment of the Vermilion Range that continues into the Yoho National Park. There are several connections to the trail from the highway, including the 10.7-km Floe Creek trail to Floe Lake campground and the 6-km Numa Creek trail to the Numa Falls campground. There is another trailhead at the Paint Pots that follows Ochre Creek with forks to the 7-km Tumbling Creek trail and the 9-km Helmet Creek trail, both of which have campgrounds. Beyond Helmut Falls the Rockwall trail continues through Goodsir Pass into the Yoho National Park. Other multi-day backcountry hikes include the Tokumun Creek trail to Fay Hut and Neil Colgan Hut, the Simpson River trail into the Mount Assiniboine Park, the Hawk Creek trail through Ball Pass into the Banff National Park, the Verdant trail from the Vermillion crossing to Banff National Park via the Honeymoon Pass and the Redearth Pass.

Day hikes with nearby campgrounds include trails on Redstreak Mountain and along Redstreak Creek, the Dog Lake trail from the McLeod Meadows campground, and the Marble Canyon to Paint Pots trail from the Marble Canyon campground. Other day hikes, of various difficulty levels, include trails to Olive Lake, to Cobb Lake, the Kindersley/Sinclair loop, the Tokumun Creek trail from Marble Canyon to Kaufmann Lake, the Kimpton Creek trail, the Hector Gorge trail, the Verendrye Creek from the Vermillion Crossing, and the Stanley Creek trail. The Dolly Varden trail along the Dolly Varden Creek (the fish was later identified as bull trout, not Dolly Varden trout) permits cycling and has a campground open when the McLeod Meadows campground closes (e.g. available for winter camping).

• 51.02504-115.980131 Kootenay Park Lodge, ☏ +1 250 434 9648, info@kootenayparklodge.com. Historic 1923 lodge with 12 cabins, restaurant and general store. (updated Jul 2018)

Numerous accommodations options are also available in Radium Hot Springs, adjacent to the southwest end of the park.

There are four front country camp sites.

• 50.6273-116.05812 Redstreak. Has drinking water, toilets, and flush showers. Some sites have electrical hook up. (updated Jun 2022)
• 50.7665-115.94143 McLeod Meadows. Unserviced. Has drinking water and flush toilets. (updated Jun 2022)
• 51.18431-116.119654 Marble Canyon. Unserviced. Has drinking water and flush toilets. (updated Jun 2022)
• 50.8135-116.01055 Crook's Meadows. Unserviced. Has outhouses for bathrooms. (updated Apr 2023)

Camping fees per night (2024):

• Unserviced $24.00-30.50
• Serviced $36.00-42.50
• o-TEN-tik glamping tents: $133.25

Backcountry use and camping permit valid at Banff, Jasper, Kootenay and Yoho national parks (2024):

• Overnight, per adult 18 and over $13.50
• Reservation $11.50
• Fire permit, per day $11.00