Hot Springs is located at 43°26′N 103°29′W, in Fall River County at the southern edge of South Dakota's Black Hills. The Fall River runs through the city. According to the United States Census Bureau, the city has a total area of 3.61 square miles, all of it land. Hot Springs has been assigned the ZIP code 57747, 

The Sioux and Cheyenne people had long frequented the area, appreciating its warm springs. According to several accounts, including a ledger art piece by the Oglala Lakota artist Amos Bad Heart Bull, Native Americans considered the springs sacred. European settlers arrived in the second half of the 19th century. They first named the city "Minnekahta" after its Lakota name. It was renamed Hot Springs in 1882, which is a translation of the Native American name. A variety of health resorts were built on the tourism offered by the springs.

Some of the attractions in the Hot Springs area are the Mammoth Site of Hot Springs and Evans Plunge, built in 1890, with its naturally warm 87 °F 31 °C spring water. The town is a great day drive to the attractions of the southern Black Hills, particularly Wind Cave National Park, Crazy Horse, Mount Rushmore and Custer State Park. Hot Springs in recognition of its historic value, the National Trust for Historic Preservation listed Hot Springs as one of its 2009 Dozen Distinctive Destinations. The city center contains over 35 sandstone buildings that offer a boutique hotel experience. 

The Angostura Reservoir, a 4,407 acres lake is located 10 miles southeast of the city and is a popular fishing, camping, and recreation area. Cold Brook Dam, which creates Cold Brook Lake is a 36 acre lake is located just north of the city, and Cottonwood Springs Dam and lake is located about 5 miles west all offer excellent fishing. Angostura offers some of the best Walleye fishing in the area. 

Hot Springs is also the home of a United States Department of Veterans Affairs hospital (Black Hills Healthcare System - Hot Springs Campus), which was designated in 2011 as a National Historic Landmark. Formerly known as the Battle Mountain Sanitarium, the 100-bed center was built in 1907 for patients suffering from rheumatism or tuberculosis. In the early 21st century, it offers extensive outpatient treatment, acute hospital care, PTSD treatment, and an alcohol and drug treatment facility. The Battle Mountain Sanitarium was declared a National Treasure by the National Trust for Historic Preservation following a December 2011 proposal announced by the Department of Veterans Affairs to close the facility. Community and state leaders, including Senator Tim Johnson, Senator John Thune, and Representative Kristi Noem opposed the closing. A concerned group of veterans and citizens organized a "Save the VA" Campaign; they have countered the VA's proposal based on the results of multiple Freedom of Information Act requests, getting as far as meeting with Secretary of Veterans Affairs Eric Shinseki to show how they believe VA leadership manipulated data to justify the proposed closure of the Landmark. After the Veterans Health Administration scandal of 2014, Hot Springs was visited by members of the United States House Committee on Veterans' Affairs for a Congressional field hearing regarding the proposed closure and the committee heard testimony from members of the Save the VA Committee and others opposed to the closure, as well as two VA administrators in favor of the closure

Hot Springs has a cool semi-arid climate bordering on a humid continental climate. Owing to its location in an area particularly prone to chinook winds, Hot Springs is one of the warmest places in South Dakota, with an annual mean temperature of 48.6 °F (9.2 °C). During the three winter months from December to February, twenty-five afternoons can be expected to exceed 50 °F or 10 °C and five winter afternoons will climb to 60 °F or 15.6 °C due to these warm winds. Nonetheless, extreme cold occurs frequently during the winter when the Föhn effect is absent: the average window for minima below or reaching 0 °F or −17.8 °C is from December 3 to February 27, and fifteen mornings get this cold during an average winter, with −20 °F or −28.9 °C reached twice per winter on average. Thirty afternoons each winter stay below 32 °F or 0 °C, with all but seven in the severe month of January 1937 not topping the freezing point. 

Snowfall averages 31.1 inches or 0.79 meters – vastly less than the extremely snowy high parts of the Black Hills – due to the very dry winters and relatively warm temperatures. The record for snowfall in a single month was 29.6 inches in April 2013, and the most in one full season was 72.3 inches from July 1975 to June 1976; in contrast, the 1988–89 season had less than 11 inches or 0.28 meters of snow all winter. The record for snowfall in a single day was 15.0 inches on March 12, 2006. The most snow on the ground was 22 inches on April 18, 1920, and the mean in January peaks at a mere 1.2 inches or 0.030 meters. 

Spring warms up early: the first afternoon climbing to 70 °F or 21.1 °C can be expected as early as March 22, and the first 80 °F or 26.7 °C maximum as early as April 22. Spring is usually the wettest season, especially in its later stages, due to occasionally very heavy thunderstorm rains. The wettest month on record was May 1935, which saw 9.65 inches of precipitation, while as the wettest calendar year overall was 1915, with 32.01 inches, and the driest was 1960, with only 6.15 inches. The most precipitation in a single day occurred on April 19, 2000, when 4.31 inches fell, part of which fell as 10 inches of snow. 

Summers are generally hot, at times uncomfortably so, although mornings tend to be fairly comfortable. On average, only two mornings each year will stay above 20 °C or 68 °F, with only three mornings on record remaining at or above 77 °F or 25 °C, although five afternoons each summer top 100 °F or 37.8 °C and forty afternoons will top 90 °F or 32.2 °C. The hottest temperature ever recorded in Hot Springs is 112 °F  which was achieved on each of three separate occasions: July 25 of 1931, July 10 of 1933, and July 10 of 1939. The fall season is usually dry and sees increasingly variable temperatures: the first freeze can be expected as early as September 23, but maxims in the eighties Fahrenheit have occurred as late as November 8 in 1999.

As of the census of 2017 Fall River County including sub-divisions 6,687 there were 3,711 people, 1,730 households, and 910 families residing in the city. The population density was 1,028.0 inhabitants per square mile.  There were 1,958 housing units at an average density of 542.4 per square mile. The racial makeup of the city was 85.4% White, 1.1% African American, 9.3% Native American, 0.5% Asian, 0.1% Pacific Islander, 0.2% from other races, and 3.5% from two or more races. Hispanic or Latino of any race were 2.1% of the population. 

There were 1,730 households of which 21.0% had children under the age of 18 living with them, 38.4% were married couples living together, 11.0% had a female householder with no husband present, 3.2% had a male householder with no wife present, and 47.4% were non-families. 42.9% of all households were made up of individuals and 20.3% had someone living alone who was 65 years of age or older. The average household size was 2.03 and the average family size was 2.79. 

The median age in the city was 49.8 years. 19.1% of residents were under the age of 18; 5.6% were between the ages of 18 and 24; 18.8% were from 25 to 44; 32.9% were from 45 to 64; and 23.7% were 65 years of age or older. The gender makeup of the city was 50.4% male and 49.6% female