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History · Keystone

Keystone dates to 1883, and 10% of its homes were built before 1940

4 places in town are on the National Register, among them a historic district with 2 buildings. Below: 5 old photos and papers, maps from 1954 on, and the census since 1980.

1883founded
4on the National Register
10%homes built before 1940
5old photos & papers
1famous people
Add an old photoShare a memory
From Keystone’s archive · credits on each photo
Quick answers

How Keystone began

When was Keystone founded?

1883

Keystone dates its founding to 1883 (Wikidata). The census first counted it in 1980.

First census: 295 in 19802020 census: 240143 years
Founding year: Wikidata. First post office: 1892.

What stands out about Keystone’s past

Read from the archive, the National Register and the record. The page puts what stands out first.

Landmarks on the Register4 places on the National Register.
★ What stands out · On the National Register

4 historic places in Keystone

The country’s official list of buildings and places worth saving.

places listed
4
National Historic Landmarks
0
none yet
historic buildings protected
8
each building in a district counts
first listed
1966
Mount Rushmore National Memorial
Mount Rushmore National Memorial, built 1925Keystone School, built 1890Keystone Trading Company Store, built 1880Lewis Byron House
BuildingsDistricts

Architectural styles listings

Log House1
Mount Rushmore National MemorialBuilt 1925
Keystone SchoolBuilt 1890
Keystone Trading Company StoreBuilt 1880
All 4 listings
Lewis Byron HouseBuilding · listed 1982

National Park Service, National Register of Historic Places. Photos from Wikimedia Commons, credited on each place’s page.

The story so far

Keystone, in brief

Wikipedia doesn’t have a history of Keystone yet. The photos, dates and memories neighbors add here are how it gets written.

Keystone is a city in the Black Hills region of Pennington County, South Dakota, United States. The population was 240 at the 2020 census. It had its origins in 1883 as a mining town, and has since transformed itself into a resort town, serving the needs of the millions of visitors to the Mount Rushmore National Memorial, which is located just beyond the town limits. Keystone was heavily damaged in the 1972 Black Hills flood. The town took its name from a local mine, which most likely was named after the keystone Masonic symbol.

Keystone was established in 1883. Between the 2010 and 2020 censuses its population fell from 337 to 240 (-29%).

Intro from Wikipedia. Population: U.S. Census Bureau.

Timeline

Keystone, 1880 to 1958

Woven from the archive, old maps, post office records, the National Register and the people born here.

  1. 19th century
  2. 1880BuiltKeystone Trading Company Store is built
  3. 1883
    FoundingKeystone is established
  4. 1890BuiltKeystone School is built
  5. 1892Post officeThe Keystone post office opens
  6. 20th century
  7. 1908In the archiveSpodumene - large crystals in granite - Etta mine
  8. 1925BuiltMount Rushmore National Memorial is built
  9. 1940In the archiveKeystone, South Dakota. Gold mining town
  10. 1954On the mapFirst mapped by the U.S. Geological Survey
  11. 1958Born hereC. D. Moore is born here
By decade

Keystone, decade by decade

2 decades in the archive, from the 1900s to the 1940s. Scroll each row; tap a photo for its story.

1900s1 item
Spodumene - large crystals in granite - Etta mine1908Spodumene - large crystals in granite - Etta mine
1910s–1930snothing yet
Nothing in the archives for these yearsWeddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Add from your album
1940s4 items
Keystone, South Dakota. Gold mining town1940Keystone, South Dakota. Gold mining townKeystone, South Dakota. Gold mining town1940Keystone, South Dakota. Gold mining townKeystone, South Dakota. Gold mining town1940Keystone, South Dakota. Gold mining townKeystone, South Dakota. Gold mining town1940Keystone, South Dakota. Gold mining town
1950s–1990snothing yet
Nothing in the archives for these yearsWeddings on Main Street, storms, parades, school pictures, the old store. If it’s in your family album, it belongs here.
Add from your album
Today11 recent
Keystone, SD 57751, USA - panoramio (8)2010Keystone, SD 57751, USA - panoramio (8)Keystone, SD 57751, USA - panoramio (7)2010Keystone, SD 57751, USA - panoramio (7)Keystone, SD 57751, USA - panoramio (5)2010Keystone, SD 57751, USA - panoramio (5)Keystone, SD 57751, USA - panoramio (11)2010Keystone, SD 57751, USA - panoramio (11)Keystone, SD 57751, USA - panoramio (10)2010Keystone, SD 57751, USA - panoramio (10)Holiday Inn Express - panoramio (1)2010Holiday Inn Express - panoramio (1)Aerial view, Mount Rushmore, near Keystone, South Dakota2009Aerial view, Mount Rushmore, near Keystone, South Dak…Untitled photo2007Untitled photoUntitled photo2007Untitled photoUntitled photo2007Untitled photoUntitled photo2007Untitled photo
On the map

Keystone on the map, 1954 to 1971

Every edition of the U.S. Geological Survey’s map of Keystone. Tap a year, or press play to watch the town change.

Keystone on the 1954 USGS mapKeystone on the 1971 USGS map1954Mount Rushmore sheet · 1:24,000

U.S. Geological Survey historical topographic maps (public domain), via Esri’s collection of the scans. The red ring marks the center of Keystone.

Then & now

Stand where they stood

No then-and-now pairs yet. Take a photo from the same spot as an old one and they appear here side by side.

Spodumene - large crystals in granite - Etta mine
Retake this viewSpodumene - large crystals in granite - Etta mine, 1908

Find the spot, match the angle, and add your photo. It becomes the first then-and-now pair on Keystone’s page.

Retake this view · +15
People over time

Keystone, census by census

0100200300198020002020Peak: 337

Between 232 and 337 people in every census since 1980.

5 censuses, 1980–2020.

U.S. Census Bureau decennial counts, from the census table on Keystone’s Wikipedia page.

Places that used to be

Places now gone and burying grounds

Keystone’s post office has been open since 1892.

Gone or out of use
Big Hit MinemineBullion MinemineColumbia MinemineDan Patch MinemineGold Hill Lode MinemineGrand Island Group MinemineHenry Tin MinemineHoly Terror MinemineJuniper MinemineKeystone MinemineLegal Tender MinemineLucky Boy MineminePeerless MinemineSitting Bull Minemine
1cemetery inside Keystone
Mountain View

US Post Offices dataset (Blevins & Helbock, CC0). Places and cemeteries from the USGS Geographic Names Information System (2021).

Help out

Finish Keystone’s story

Most archives stop around 1920. The photos from after that are in family albums, not libraries.

Decades since 1900 with photos
00s10s20s30s40s50s60s70s80s90s
2 of 10 decades. The empty ones are waiting for someone’s album.
Retake an old viewSpodumene - large crystals in granite -…: stand where they stood+15Share a family photoSign in to add one+10

Questions about Keystone’s history

What year was Keystone founded?

In 1883, according to Wikidata. Keystone’s post office opened in 1892, and the census of 1980 counted 295 people here.

What is on the National Register in Keystone?

4 listings: 3 buildings and 1 historic district, the Mount Rushmore National Memorial, with 2 contributing buildings. 8 historic buildings in all.

Memory lane

What the archives can’t tell you, neighbors can.

Town Square →
Start a conversation
Sources

Where this page comes from

Founding dates: Wikidata, Wikipedia, the U.S. post office records of Blevins & Helbock (CC0) and the Census. Homes by year built: Census ACS 2020–24. National Register of Historic Places: National Park Service (list of May 22, 2026). Old photos, postcards and papers: Wikimedia Commons, the Library of Congress and other public archives, credited on each item’s page. Maps: U.S. Geological Survey historical topographic maps (via Esri) and Sanborn fire-insurance maps (Library of Congress). History text and census tables: Wikipedia (CC BY-SA 4.0). Places that used to be: USGS Geographic Names Information System (2021). How TownRatings grades history →

From Wikimedia Commons (11), the Library of Congress (5), Wikidata (2), the National Register of Historic Places (4), Wikidata and Wikipedia for famous people, U.S. Geological Survey historical maps, U.S. Census counts (via Wikipedia), the US Post Offices dataset (Blevins & Helbock) and the USGS Geographic Names Information System. Archive images are copied here with their credits and licenses, shown on each photo’s page. Refreshed monthly.